Atwater CA Castle Air Museum KC-135 (#0029)

A Boeing KC-135 that was used in aerial refueling. Introduced into service in 1957, the KC-135 (with various modifications) is still the main aerial refueling aircraft for the US Air Force. Though appearing similar to the Boeing 707, it is a quite different aircraft (see the Wikipedia). If you follow military procurement/aviation industry news, you'll know that finding a replacement for this aircraft has been an ongoing debate since 2003. en.wikipedia.org/wiki/Boeing_KC-135_Stratotanker