Other armed forces branches interested
According to Pratt and Whitney, its XA100-series engine is at least 25% more efficient than the F135 currently used on the F-35. They also claim it can provide 10- to 20% more thrust.
This work was part of the USAF’s former Adaptive Engine Transition Program (AETP), which was scrapped in 2023 to upgrade the existing Pratt & Whitney F135 engine. However, additional funding was made available last year for AETP to continue.
Beyond the USAF, other United States armed forces branches have also shown signs of interest in the NGAP engines. But this is not a certainty, especially with the United States Navy heavily invested in its 6th-gen carrier-capable stealth fighter called the F/A-XX.