The US military’s fighter fleet is projected to become stealthier but less available, widening the gap between technological sophistication and the combat mass needed for a prolonged war. The nonpartisan agency projects the US Department of Defense’s (DoD) total fighter force will shrink to 3,000 aircraft by 2029 before rebounding to 3,600 by 2040. By 2040, CBO estimates US Air Force fighter availability will drop to 45% and US Navy availability to 35%. Gunzinger and Penney argue that Collaborative Combat Aircraft (CCA) would supplement rather than replace crewed fighters, adding sensing, electronic warfare and weapons capacity. However, adopting CCAs to address the problem of fighter mass has its own set of challenges.