House and Senate versions of the FY2026 NDAA offer competing visions for the Air Force’s refueling fleet, threatening to disrupt a newly minted modernization strategy.
On Oct. 8, 2025, the United States Senate passed its version of the Fiscal Year 2026 National Defense Authorization Act (NDAA) after the House of Representatives approved its version of the defense bill earlier in September. While both chambers must still negotiate and vote on a compromise bill before it is signed into law, the 2026 NDAA is poised to substantially alter the structure of the Air Force’s strategic aerial refueling fleet.
Strategic aerial refueling aircraft, also known as tankers, are the fundamental backbone of the U.S. military’s ability to project power across the globe. Tankers enable aircraft to fly longer and further by offloading fuel in-flight to a receiving aircraft.
Aging fleet modernization
The US tanker fleet, composed of a projected 466 aircraft at the start of fiscal year 2025, is undergoing a large-scale modernization effort that aims to retire aging aircraft and procure new capabilities. The Boeing KC-135 Stratotanker, first delivered to the Air Force in 1957, constitutes roughly 80% of the tanker fleet and is the oldest fleet operated by the Air Force at an average age of over 63 years old.
In 2011, the Air Force awarded a contract to procure 179 KC-46A Pegasus to replace roughly one-third of the KC-135 fleet. The first KC-46 was delivered to the Air Force in 2019, and the final aircraft is expected to be delivered around 2029.
Beyond the KC-46
The KC-46 program only represents the first phase of tanker modernization. The Air Force planned follow-on programs for years, but they have only served as rough guidelines for defense planners and have been subject to often dramatic change.
In 2023, the Air Force announced it would abandon two programs, KC-Y and KC-Z, in favor of a plan to procure 75 additional KC-46 aircraft and accelerate efforts to develop and field a tanker aircraft with advanced capabilities, dubbed the Next Generation Air-Refueling System (NGAS). The Air Force cited concerns that competitive procurement for a full-scale tanker program would slow refueler modernization efforts and push back the deployment of advanced capabilities.
In July 2025, the Pentagon announced that it would proceed with plans to procure an additional 75 KC-46 aircraft and authorized the contract in October.
House restrictions on procurement
However, provisions included in the House’s version of the NDAA could threaten to derail it. A provision included by the House Armed Services Committee would limit the Air Force from procuring KC-46 past a total of 183 aircraft until the Secretary of Defense certifies that the Pentagon “has developed and is implementing a plan to correct critical technical deficiencies with the KC-46”.
Persistent technical issues
The KC-46 has proven troublesome for the Air Force, with Congressional concern centered on persistent technical issues. Chief among them is the aircraft’s Remote Vision System (RVS), which replaced the viewing window used by boom operators with a computerized camera and sensor system. The Air Force ordered Boeing to redesign the system due to clarity and glare issues that could jeopardize refueling operations.
While Boeing’s updated RVS 2.0 addresses many of these issues, it has slipped three years behind schedule, with approval likely in 2027 – meaning most of the 179 original aircraft will require retrofits. The aircraft has also faced other critical deficiencies, including an overly stiff refueling boom that resulted in multiple serious incidents – the most recent of these being in July 2025. Despite these challenges and delays, the KC-46 continues to support combat operations with an increasing role in the Air Force’s refueling operations.
Wild ATC audio, a lost tail boom and live missiles turns into quite the story 👀
NOBLE42 (F-15E Mountain Home AFB) had a incident with WIDE12 (Boeing KC-46 17-46028) yesterday near Santa Barbara, California while refueling during a CAP (Combat Air Patrol) which was enforcing a… pic.twitter.com/VkIJJZ1OIT
— Thenewarea51 (@thenewarea51) August 23, 2024
Key members of the House Armed Services Committee, such as Chairman Mike Rogers (R-AL), have been vocal critics of the KC-46 program and previous defense authorization bills have aimed to prevent or slow further KC-46 procurement.
Additional House and Senate provisions
The House version of the fiscal year 2026 NDAA further proposes a cut of $300 million in procurement for the KC-46, which could result in a decrease of delivered aircraft per year, and an $80 million cut to research and development funding for new capabilities for the aircraft.
The House also included provisions that prohibit the retirement of primary mission KC-135s operating with the Air Force Reserve and increase the congressionally-mandated tanker fleet minimum of 466 aircraft to an incremental 504 aircraft by 2027 – resulting in a likely pause in retiring and replacing older KC-135s as new KC-46 enter service.
The House bill further requires the flight-ready preservation of retired KC-10 Extenders, which the Air Force removed from service in Sept. 2024. Many of the KC-10 stored at the aircraft boneyard at Davis-Monthan Air Force Base have refueling booms and engines removed, raising questions about restoration feasibility.
The Senate-passed version of the NDAA only contains one provision related to tanker aircraft. The provision requires the Secretary of the Air Force to retain and reassign any KC-135 replaced by incoming KC-46, but unlike the House NDAA, the Senate version establishes a criterion for retention based on available manpower and training availability.
What happens next
The process for reconciling the differing versions of the NDAA remains uncertain, with lawmakers likely to engage in either informal negotiations or convene a formal conference committee. It remains likely that NDAA reconciliation will not be an immediate priority for Congress as negotiations to end the current government shutdown will likely remain the main focus over the next weeks.
However, it is clear that political leaders in both chambers and across the aisle share a common goal: to maintain and expand the tanker fleet to better position the U.S. military for potential conflicts on the horizon.
