The president did not specify what the F-55 will be able to do, how much it might cost, or where it is in the procurement process.

Trump appeared to indicate that the “F-55” would be a two-engine version of the F-35, but such a modification would require a comprehensive redesign of the airframe, essentially resulting in a new airplane.

The president has said that his administration is looking to develop a new fighter that will be a "substantial upgrade" from current models.