3. In combination, an airframe having a fuselage and wings, a jet motor detachably mounted on the fuselage in substantially parallel relation thereto, the airframe having one center of gravity with the motor mounted thereon and a second center of gravity with the motor detached therefrom, a booster rocket disposed within and substantially parallel with said fuselage, a pair of rocket supporting tracks having their upper surface below the rocket center and adapted to support the rocket in one position or in a second position wherein the rocket is turned 180* about its longitudinal axis, driving lugs extending diametrically and transversely from the front end of the rocket and resting on said tracks, thrust abutment means on the fuselage for said driving lugs, a pair of vertically extending lugs on the rocket near the rocket rear portion, means on the fuselage for sideways holding said vertical lugs, latch means for longitudinally holding the rocket in place, and a rearwardly extending exhaust nozzle on the rocket, said nozzle being canted from the longitudinal center line of the rocket so that the nozzle center line in one position passes through one of said centers of gravity and when the rocket is turned 180* about its longitudinal center line the nozzle center passes through the other one of said centers of gravity.