T-37 Tweetie BirdCessna T 37 Tweety Bird airplane model. The T 37B became operational in 1959. The T 37B has improved radio navigational equipment, UHF radio and redesigned instrument panels. Many air forces fly the T 37B, including those of Thailand, Greece, Chile, Jordan, Turkey and Pakistan. Students from 12 North Atlantic Treaty Organization countries train in T 37B's at Sheppard Air Force Base, Texas. The preflight phase of Specialized Undergraduate Pilot