"There may not be as much of an open wallet for every defense program as I think some people had anticipated," said Katherine Blakeley, a research fellow at the nonpartisan Center for Strategic and Budgetary Assessments.
Lockheed's F-35 fifth-generation fighter and Boeing's KC-46 Pegasus aerial tanker are also priorities as is Northrop's B-21 stealth bomber.
"The Air Force has the largest ramp-up in acquisition spending of the services in the 2020s," said Blakeley. "That's partly a function of all these programs happening at the same time."