Improving Interoperability with Allies and Partners

The U.S. Air Force (USAF) must be able to generate and sustain airpower from a wide variety of dispersed and often partner-owned locations. This requirement underpins Agile Combat Employment (ACE), the USAF’s concept for increasing survivability and operational flexibility by shifting operations away from centralized, vulnerable air bases to a network of smaller, distributed sites.⁠^[1] Although the Air Force has traditionally brought its own equipment and support to forward theaters, effective and affordable execution of ACE increasingly depends on the ability of the USAF to operate from partner airfields. As recent USAF doctrine and analysis emphasize,⁠^[2] this places a premium on interoperability, broadly defined as the ability “to act together coherently, effectively and efficiently to achieve tactical, operational and strategic objectives.”⁠^[3]

The RAND Project AIR FORCE (PAF) framework outlined in this brief treats partner interoperability not as a single end state but as a spectrum of cooperation that must be defined for each mission area. In this view, interoperability is tailored to operational requirements, agreed standards, and partner capabilities, rather than pursued as an abstract objective. Achieving this interoperability requires the USAF to rely on allied and partner nations for capabilities and services that enable operations in locations where the United States lacks a permanent presence.

If the USAF can leverage aircraft servicing and base operating support capabilities at partner air bases, ACE operations can become more agile and scalable. Foregoing the need to rely exclusively on dedicated personnel and equipment reduces the strain on USAF transportation and logistics and shortens deployment timelines; ACE also better sets the theater for sustained operations. Just as critically, it assures commanders in the United States and in allied nations that they can generate combat power reliably from multiple locations, strengthening deterrence by demonstrating credible and persistent airpower.

For these reasons, United States Air Forces in Europe–Air Forces Africa (USAFE-AFAFRICA, henceforth USAFE) seeks to enhance interoperability with joint and allied partners, focusing on manpower-intensive and equipment-heavy functions, such as aircraft maintenance and base operating support (BOS). In fiscal year 2024, the command enlisted PAF’s help in identifying key obstacles to greater interoperability and in recommending actions to overcome them. USAFE-AFAFRICA staff had been pursuing interoperability, but those efforts were generally siloed within individual divisions and branches. USAFE-AFAFRICA/A4 (the Directorate of Logistics, Engineering, and Force Protection) asked PAF to help address the obstacles to partner interoperability in a more comprehensive and proactive manner.

PAF developed a framework that USAFE can use to assess partner capabilities, identify gaps between those capabilities and USAFE’s needs, and develop courses of action (COAs) to close those gaps. PAF then applied that framework to the functional areas in the scope of its analysis, identified organizational and institutional barriers, and recommended steps to overcome those barriers.

PAF’s research uncovered USAFE-wide challenges that transcended individual functions—concerns about communication, coordination, and planning. Those cross-cutting issues emerged organically and revealed structural barriers that hinder efforts to achieve effective interoperability. Although functional gaps remain important, addressing those shared institutional challenges is essential to the progress of ongoing and future efforts toward interoperability.

A Framework for Pursuing Partner Interoperability

PAF’s research focused on a concept of interoperability tailored to USAFE’s goals and needs for the functional areas it examined (i.e., aircraft cross-servicing and BOS). So, in contrast with the interoperability entailed in, say, conducting joint air operations, it addressed specific operational contexts, such as the following:

• the United States leveraging the aerospace ground equipment of a partner nation to perform its own aircraft servicing and maintenance
• the United States relying entirely on a partner nation for a capability (e.g., aircraft arresting systems, airfield damage repair)
• the United States dividing responsibility for a capability with a partner nation (as is sometimes done for firefighting or force protection).

North Atlantic Treaty Organization (NATO) terminology generally employs the term partner nation to refer to the host nation in which operations occur, while the United States is sometimes referred to as the sending nation.⁠^[4] The latter term serves as a reminder that while PAF’s work focuses on the United States, the principles of interoperability outlined here could apply equally to operations involving any two countries.

The PAF framework for improving and sustaining partner interoperability is summarized in Figure 1. The initial process of setting an interoperability goal involves three components: establishing operational needs, determining standards of performance, and assessing partner interest and alignment with U.S. objectives. Within this process, it is important to note that the United States should determine its needs and identify the capability gaps it wants to fill to effectively assess the partner’s interests and alignment. PAF emphasizes that partner willingness, strategic alignment, and absorptive capacity—i.e., the partner’s institutional and manpower ability to sustain new capabilities—are essential determinants of which goals are realistic.

This flowchart illustrates the process for achieving partner interoperability. It begins with the goals of partner interoperability at the top, which include:

• Operational needs
• Standards of performance
• Partner interest and alignment

Partner capability assessment

First box on the left represents "Partner capability assessment" and includes two main sections.

Standards and requirements

USAF enterprise and/or theater standards to specify needed capability, compatible with interoperability.

Perform assessments

• Priority and resources to perform assessments
• Access to host nation (HN) base, facilities, and equipment
• Information systems to store and distribute assessments

Develop and evaluate COAs

The middle box represents "Develop and evaluate COAs" (Courses of Action), consisting of two subsections: Develop COAs and Evaluation criteria.

Develop COAs

• Develop and update agreements
• Develop and maintain familiarity between U.S. and HN
• Train HN personnel
• Provide materiel solution to HN
• Maintain HN equipment
• Rely on U.S. capabilities in total or in part

Evaluation criteria

• Compatibility: With HN ability, willingness, and priorities
• Cost: Both financial costs and staff and wing levels of effort should be considered
• Benefits: Alignment with operational requirements

Execute

The rightmost box represents "Execute" and includes the following activities:

• Communicate status and progress
• Implement COAs
• Maintain relationships with HN
• Update agreements

Arrows indicate the process flow from setting goals of partner interoperability to conducting partner capability assessments, developing and evaluating COAs, and finally executing agreements and actions.

NOTE: HN = host nation.

Once the goals of partner interoperability are established, the United States needs to assess the partner’s capabilities using the standards that initially drove the requirement for interoperability in the first place. Next, it needs to develop and evaluate COAs that will enable the partner or host nation to provide those capabilities. Finally, the United States must implement those COAs using security cooperation guidelines and other tools, and it must institute concrete measures to maintain the relationship with the partner. The framework is intentionally iterative, linking needs, standards, assessments, and execution in a closed‑loop process.

One issue of primary importance in this process is the need for USAFE to articulate clearly what its interoperability goals are: In particular, what capabilities does USAFE want or need to develop in conjunction with the partner nation? PAF found that existing guidance, such as that found in the ACE concept of employment, Mission Guidance Letter, and country plans, does not yet provide a coherent demand signal linking interoperability needs with specific operational plans. This leaves priorities fragmented. Beyond specifying and prioritizing its goals, the command needs to make them clear to all the parties involved, especially the partner nation. That can prove challenging to large, complex organizations, such as USAFE, but it is essential to producing effective partnerships.

PAF applied this framework to its examination of the aforementioned functional areas, aircraft cross-servicing and BOS. Within those broad areas, the PAF team considered two operational use cases of cross-servicing and maintenance and four use cases of BOS. Those specific use cases are outlined in the discussion that follows.

Aircraft Cross-Servicing and Maintenance

PAF identified three cardinal benefits to USAFE’s pursuit of aircraft cross-servicing:⁠^[5]

• Improved response times: If the pilots and their aircraft can immediately deploy to a forward location without waiting for home-station support, they can demonstrate greater responsiveness.
• Reduced logistics burdens: If maintainers can count on at least some mutual support and/or available equipment, that will reduce the transportation burden and cost.
• Greater flexibility and resilience: If there are more locations available to provide basic capabilities, pilots and mission planners have more options at their disposal.

When PAF began its research, USAFE staff had been aggressively pursuing F-35 cross-servicing capability and initially asked RAND to support those efforts. As barriers to F-35 interoperability were cleared, the project scope expanded to include F-16 cross-servicing capability and the use of partner nation support equipment (SE), both of which presented additional challenges and opportunities.

Significant progress has been made in enabling F-35 basic cross-servicing: Several regulatory and technical barriers have been resolved, and partners are now conducting unsupervised servicing of U.S. aircraft. However, two categories of F-35 tasks—secure weapons servicing and maintenance requiring the maintenance-vehicle interface—still require technical modification and, therefore, meaningful investment. The PAF analysis emphasizes that USAFE should pursue such modifications only where the operational payoff is clear, because their value varies across ACE maneuver operations, hub-and-spoke operations, and sustained combat operations, and some tasks will remain restricted for security reasons.

F-16 cross-servicing and the use of partner nation SE introduce additional considerations. The primary obstacle for SE is uncertainty over the authority and risk acceptance required to use partner equipment. USAFE should clarify who is responsible for accepting this risk and establish appropriate policy. More broadly, USAFE should specify the level of maintenance capacity it requires from partners for its operational concepts to be executable and communicate those expectations clearly.

Taken together, these findings point to a broader need for USAFE to define its desired end state for aircraft cross-servicing and what levels of interoperability it seeks across aircraft types and mission areas. Once these objectives are clearly stated, planners can more effectively determine when technical modifications or new agreements are worth the cost. This includes, for example, specifying the operational benefit of F-35 weapon-loading interoperability or F-16 pre-flight and basic post-flight cross-servicing capability.

Base Operating Support

Within the category of BOS, PAF focused its attention on four functions or capabilities: aircraft arresting systems (AAS); airfield recovery, and specifically airfield damage repair (ADR); fire and emergency services; and force protection. Those areas were selected because they place particularly high demands on the deploying unit, in terms of equipment and vehicles, manpower, or both.

Aircraft Arresting Systems

AAS are critical safety features designed to ensure that fighter aircraft can safely stop during emergency landings or aborted takeoffs. Because those systems are safety-critical and highly technical, successful interoperability depends on accurate assessments of a partner’s capabilities, disposition, and alignment with the United States’ operational needs. Some partner nations use AAS provided by the United States, others use their own systems, and still others do not have any AAS, either because they do not conduct fighter operations or because they employ other safety measures. The issue is complicated by the fact that partner nations with U.S.-provided systems do not always maintain them to USAF standards, which can require USAFE to devote its resources to their maintenance. The challenges to pursuing AAS interoperability are therefore numerous and complex.

USAFE does not have a coherent institutional approach to assessing AAS interoperability with partner nations, nor does it have the capacity and resources to conduct such assessments. This gap is less about inspecting AAS hardware—which civil engineers already do—than about evaluating each partner’s overall AAS enterprise, maintenance posture, and capacity for a sustainable partnership. The command could benefit from adopting a structured approach to assessment. PAF recommends adopting a clear, formalized, and replicable rubric to ensure that decisions about interoperability are consistent and reflective of existing resources.

Another recommendation is to assign the responsibility of interoperability assessment to a dedicated organization, such as the 435th Construction and Training Squadron. Alternatively, USAFE could establish an echelon above the wing level to address the broader variety of interoperability challenges. The key point is that achieving effective interoperability requires the dedication of manpower and resources.

Airfield Damage Repair

USAF airfield recovery involves rapidly restoring air base operations after an attack or natural disaster to ensure that aircraft can continue to take off, land, and be serviced. A critical aspect of this is ADR, which consists of assessing damage to runways, taxiways, and critical infrastructure and quickly restoring those areas to operational status. USAFE personnel have relatively little knowledge of partner nations’ ADR capabilities simply because they have not observed those capabilities in peacetime operations. USAFE/A4C (the Civil Engineering Division) has initiated efforts to assess partner nations’ capacity to perform ADR; nonetheless, PAF notes that, among the four functional areas of BOS that it analyzed, ADR presents, by far, the most challenging picture.

Establishing a theater-wide ADR capability that USAFE and NATO partners could sustain would require coordinating three lines of effort that focus on training, materials, and equipment, respectively. PAF specifically endorses NATO’s emerging use of fiber‑reinforced polymer (FRP) materials as a practical, scalable solution for ADR and recommends that USAFE support this initiative within a comprehensive campaign plan. PAF emphasizes the importance of developing a clear and actionable plan to ensure that the necessary resources are secured to develop an ADR capability that benefits all partner nations.

Fire and Emergency Services

At USAF air bases, fire and emergency services teams are specialized units trained in rapid response to aircraft emergencies, such as crashes or fires. They are equipped with a variety of firefighting and aircraft rescue vehicles specifically designed to handle aircraft fires. While USAFE wings rely almost entirely on partner nations’ firefighting resources when forward-deployed, they often deploy with small teams of firefighters who advise and assist each partner nation as necessary. This is particularly true when a partner nation does not operate the same aircraft as the United States and thus is unfamiliar with the specific crash and rescue needs related to USAF aircraft. Indeed, the requirement to deploy USAF firefighters often originates with the partner nation rather than with the United States.

However, apart from the demands imposed by specific aircraft, USAFE operators expressed high confidence in partner nations’ firefighting and crash and recovery capabilities, and for the most part they did not anticipate needing to deploy organic firefighting capabilities during wartime. This is largely because the standards for fire and crash and rescue operations at USAF bases are based on both USAF requirements and NATO or international guidelines. Those standards align with NATO standardization agreements and other international guidelines to ensure interoperability and consistency of safety measures across allied air forces. Having said that, PAF notes that continued engagement, familiarization, and data collection remain important, particularly in light of personnel turnover and the need to verify capabilities at individual locations.

Force Protection

Force protection involves maintaining the security of an air base, its personnel, and assets from threats that may arise within or beyond its perimeter. Force protection functions include physical security, surveillance, access control, and base defense. When USAFE fighter wings deploy to a partner nation’s air base, they rely almost exclusively on the partner nation for base and airfield perimeter security. However, small teams of U.S. security forces are used to protect aircraft and classified operations. Within USAFE, the attitudes regarding partner nations’ security were mixed: The general consensus among observers was that few countries maintain comprehensive security practices at the same level as the USAF. PAF found significant disparities in the force protection practices of different countries. In particular, it found that NATO allies who had been part of the Soviet Union needed to make improvements in the areas of training and facilities to bring their force protection capabilities in line with U.S. standards.

PAF observed that the principal obstacles to force protection interoperability stem from coordination shortfalls within USAFE’s headquarters processes rather than from the quality of work in any single directorate. Logistics, Engineering and Force Protection (A4S) already employs a well‑structured process for assessing partner capabilities and developing agreements that emphasize complementary force protection roles, but information from the planning (A5), operations (A3), and logistics and support (A4) staffs is not always synchronized early enough for A4S to plan and position resources efficiently. As a result, that division often must take additional steps to meet emerging taskings. PAF therefore recommends improving cross‑directorate communication and planning cycles—thus ensuring that A4S’s effective partnering process is coordinated with A3 and A5 earlier—to provide a more deliberate and predictable approach to force protection planning.

Findings and Recommendations

PAF’s companion reports on partner interoperability conclude that USAFE’s greatest obstacle is not hardware or policy but coherence. Fragmented communication, diffused authority, and uncertain goals limit progress across the base support and maintenance functions. Addressing these barriers together would turn interoperability from a series of scattered efforts into a sustained mission.

Institutional coherence and coordination. Communication and planning remain fractured across the headquarters and wings, and no organization owns interoperability as an enduring mission. Establishing a small, permanent Partner Interoperability Planning Cell—embedded within the A staff but linked to wings and NATO partners—would provide theater‑wide integration, shared information, and continuity across rotations.

Guidance, roles, and prioritization. Existing documents—the Operating Instruction, Air Campaign Support Plan, and country plans—do not clearly define responsibilities or measurable objectives. Embedding interoperability goals and metrics into the updated Air Campaign Support Plan and expanding the Operating Instruction to specify coordination across headuqarters and subordinate units would allow USAFE to align efforts and resources. Incorporating A4 requirements into country plans would better connect operational needs with security cooperation programming.

Leveraging security cooperation and capacity-building tools. USAFE underuses mechanisms, such as Section 333 funding, State Partnership Programs, and advisor units. A multiyear campaign approach could transform single events into sequenced engagements that build partner engineering and logistics capacity. Training venues—such as Silver Flag, the Ground Combat Readiness Training Center, and the Inter‑European Air Forces Academy—offer platforms for recurring instruction supported by consistent partner­‑capability assessments.

Finally, the strategic implications of interoperability make these changes timely. USAFE cannot assume that wartime urgency will resolve peacetime shortfalls. Achieving day-zero interoperability requires deliberate preparation through doctrine, training, and repeated practice. Doing so would improve European readiness, ease U.S. deployment demands, and support a broader U.S. focus on the Indo-Pacific region. Taken together, these findings show that USAFE can achieve credible interoperability only by treating it as a continuous, measured, and resourced mission—one that integrates staff coordination, functional execution, partner development, and theater strategy.

Notes

1. Air Force Doctrine Note 1-21, Agile Combat Employment, U.S. Air Force, December 14, 2022; Air Force Doctrine Publication 3-0, Operations, U.S. Air Force, January 22, 2025. Return to content ⤴
2. See, for example: Air Force Doctrine Note 1-21, 2022; and Sandeep Mulgund, “Agile Combat Employment Interoperability and Integration,” Wild Blue Yonder, Air University, December 18, 2024. Return to content ⤴
3. NATO, “Interoperability: Connecting Forces,” webpage, last updated April 11, 2023; Joint Publication 1-02, DoD Dictionary of Military and Associated Terms, Office of the Chairman of the Joint Chiefs of Staff, last updated November 2021. The NATO definition emphasizes the idea of members of the alliance operating together, while the definition in the DoD dictionary is broader and includes security cooperation and contexts unrelated to NATO. Return to content ⤴
4. NATO, Allied Joint Publication 4-3, Allied Joint Doctrine for Host-Nation Support, Edition A, Version 1, NATO Standardization Office, April 2021. Return to content ⤴
5. In the context of this research, cross-servicing refers to a situation in which a partner nation provides operational or logistics support to U.S. aircraft to ensure that those aircraft are mission-ready. Such support could include refueling, rearming, maintenance checks, and other ground services. Return to content ⤴

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Topics

• Aviation Maintenance
• Battle Damage Assessment and Repair
• Europe
• Fighter Aircraft
• Rapid Force Deployment
• Security Cooperation
• United States Air Force