The Air Force hopes to ramp up to 386 squadrons by 2030, but it could face challenges just to maintain its current size.
The Congressional Budget Office estimates that the service would need significantly more funding annually than it has received in recent decades simply to replace aging airframes.
The Air Force has about 5,600 aircraft, many of which are nearing the end of their service life, the nonpartisan research group noted in a recent report, "The Cost of Replacing Today's Air Force Fleet."
CBO estimates that replacing the planes in the current fleet one-for-one would cost an average of $15 billion a year (in fiscal year 2018 dollars) in the 2020s. That figure would rise to $23 billion in the 2030s and then drop back down to $15 billion in the 2040s. In comparison, appropriations for procuring new aircraft averaged about $12 billion per year between 1980 and 2017, and just $9 billion between 2010 and 2017, the report noted.
"In CBO's projection, the procurement costs of new aircraft... would rise to and remain at levels considerably above historical averages," it said.
Fred Bartels, a defense budget analyst at the Heritage Foundation's Davis Institute for National Security and Foreign Policy, said the Air Force is at risk of shrinking due to fiscal constraints, especially as other services such as the Navy seek to beef up their own force structures in the coming years. Even if the Air Force doesn't decline in size, modernization and force level increases could be delayed, he noted. "I can see the growth being slowed down a little bit here and there."
To maintain force structure, the Air Force might have to resort to life-extension efforts, he said. But that creates its own set of problems.
"Your aircraft cost even more to operate because you're... [holding] together a 50-year-old airplane,"...