But there is basic and basic.
An example is the NATO AEW Force. Rather than pound the circuit in an expensive, in all senses, NE3A they procured similar 707 aircraft which offered the dual capability of their own organic transport aircraft to service FOB and FOL and also for pilot continuation training.
A similar effect might be achieved for a high performance fighter by using a similarly configured aircraft without the full mission avionics suite. That would reduce maintenance bill and probably increase its flight line availability too.