Abstract: This invention relates to a method and apparatus whereby functioning airborne conventional aircraft and engine combinations may be assisted during flight in attaining above normal airspeeds and/or altitudes; for the purpose of improving their performance during flight. In the method steps, well known apparatus elements, and/or new and useful combinations thereof, are utilized to enable such aircraft to achieve flight advantages, and improved flight performance, not believed to be possible prior to this invention. According to the method, booster apparatus is used initially in acquiring altitude, forward momentum of the aircraft, rotational momentum of its rotor airfoils, and the like. Apparatus used includes oxygen booster systems. Such systems can include forward thrust rockets, rotational boosters, and apparatus for injecting a supplemental oxidizer into a gas turbine engine afterburner.