June 24, 2009: On June 17th, the last of nearly 79,000 American military student pilots flew a T-37B jet trainer. After half a century, the T-37B has retired. One of the most successful aircraft designs of the post-World War II era, the Cessna T-37 is a two engine primary jet trainer with a top speed of about 680 kilometers an hour. Designed in 1953, the three ton T-37, affectionately nicknamed the "Tweet," entered service with the Air Force in 1957. Through the 1960s, 1,268 T-37s were produced in several models, including a ground attack version, the A-37, which has a much higher speed (830 kilometers an hour) and somewhat different overall characteristics. Most T/A-37s were still flying at the end of the Cold War. But since then, they have been retired at a rapid rate.

The versatile T-37 proved an attractive investment for nations wishing to stretch their defense dollars, and was procured for use by the U.S. and 14 other countries. The oldest T-37s have logged over 20,000 hours of flight time, with the average well over 12,000 hours. 

By 1996, all USAF T-37Bs completed a SLEP refit, extending their total useful life to over 30,000 hours. Regarded as a "user friendly" aircraft, by now many T-37Bs are basically worn out. The T-6A was selected as its replacement because this aircraft, based on the very popular Pilatus PC-9, already had an excellent reputation as a trainer aircraft. A single engine prop driven aircraft, the T-6A,  reduces fuel costs by over 60 percent. The three ton T-6As cost about $8 million each.

But many nations still prefer the tweet, and the United States is constantly asked to provide some of its retired (to the bone yard) T-37s. Last year, for example, the U.S. donated twenty pre-owned T-37 jet trainers to Pakistan. The T-37s were being taken from the U.S. storage facility (the "bone yard"), refurbished and shipped to Pakistan (which paid for the shipping).

So while the Tweet no longer flies in American colors, it will be found around the world for another decade or so.