<hi style=afpcap>The Boeing developed flying boom inflight refuelling system was quickly adopted as the standard method of aerial fuel transfer with three C-97A Stratofreighters being modified as tankers in 1950. These were designated KC-97As with the Air Force performing evaluation before placing an order for 60 KC-97E models in 1951. This was followed by the KC-97F with 159 examples being produced which had slightly more powerful engines. However it was the KC-97G version which was ordered in greater numbers than any other with 592 being built before the last example (illustrated) was delivered to the Air Force in November 1956. No sooner had the final KC-97 been delivered than the early production versions began being retired from service by the KC-135A. However many of the displaced KC-97s were modified into freighters with the flying boom removed, most joining the Air National Guard. In addition almost 100 KC-97Gs were fitted with a pair of J47-GE-25A jet pods as KC-97Ls to increase their performance. These served the Air National Guard from the mid '60s until the mid '70s enabling frontline tankers assets to concentrate on the massive air refuelling requirement in South East Asia. </hi>
