My dad was a career U.S. Air Force fighter pilot.  After returning from combat duty in the Korean War, he did a tour of duty as a ferry pilot.  He made the North Atlantic crossing many times in single-engine jet fighters, often in winter.  The planes usually crossed in flights of two or more aircraft.  My dad said that he and his squadron mates had an informal agreement: If one of them had an engine failure, another one would get behind the troubled aircraft and try to <i>push it</i> to maintain air speed. Fortunately they never had to try it.