The U.S. Air Force’s Next Generation Air Domination (NGAD) program may be the most expensive airline program in history. Each sixth-generation manned aircraft is expected to cost hundreds of millions of dollars.

This was stated by US Air Force Secretary Frank Kendall. He didn’t specify a specific figure, but said it wasn’t in the hundreds of millions. “It’s a number that will catch your eye. It’s going to be an expensive plane,” Kendall said.

The cost of NGAD will reportedly be more than double that of the F-35. The fifth-generation aircraft currently costs at least $80 million.

Kendall said the NGAD would be “incredibly effective” but would need to be accompanied by cheaper platforms such as autonomous drones to expand its combat capabilities.