Back in 2009, the Navy and the Air Force secretly shook hands on a new way to work together to fight future wars against major powers. It’s called AirSea Battle, and not much about it has been made public. But the Air Force’s second in command publicly fretted on Wednesday that some of its core components might not be affordable.

The basic concept behind AirSea Battle is to maintain U.S. dominance of the air and sea, as the Navy War College’s Milan Vego writes in this month’s Proceedings, and overpower any nation that might try to push the United States back from its shores through advanced...