Supersonic speeds would certainly be used for beyond visual range (BVR) engagements. Higher speeds mean you and your missiles have more energy and maneuverabili

Supersonic speeds would certainly be used for beyond visual range (BVR) engagements. Higher speeds mean you and your missiles have more energy and maneuverability. Since the F-35 needs to use it's afterburners to reach supersonic speeds, it likely wouldn't use the extra fuel just for transport.