The 549th Combat Training Squadron is a non-flying United States Air Force unit. It is assigned to the 57th Operations Group, and is stationed at Nellis AFB, Nevada. It conducts air support and air interdiction sorties in "Green Flag (West)" exercises to train USAF fighter pilots and the aerospace power component to the US Army's brigade combat training.The unit was originally formed as the 549th Night Fighter Squadron in 1944.