One billion dollars earmarked in the Pentagon’s forthcoming 2015 budget request will support a new development program “in the next few years” to produce an engine beyond that used for the F-35, says Frank Kendall, undersecretary of defense for procurement.

Pratt & Whitney and General Electric are already working through the Adaptive Engine Technology Development (AETD) program to design engines 25% more efficient than today’s and producing 10% more thrust.

The goal is to develop an engine that will eventually replace or surpass the F135 built by Pratt & Whitney for the F-35.

This is “$1 billion that wasn’t there last year,” says Air Force Undersecretary Eric Fanning. It is unclear how much of this money is new and how much adds on to efforts already underway.

Kendall called out engine technology as an area of development in which the Pentagon must maintain an edge. “One of the technologies we lead in is the high performance. We want to stay there,” Kendall says.

Kendall emphasizes that there is funding in the 2015 budget plan, which will be released March 4, for competitive prototyping to both reduce risk and stimulate industry. It is unclear whether this engine program will include enough money for full prototypes, but it looks likely.