The AT-9 advanced trainer was used to bridge the gap between single-engine trainers and twin-engine combat aircraft. The AT-9 was not easy to fly or land, making it particularly suitable for teaching new pilots to cope with the demanding flight characteristics of a new generation of high-performance, multi-engine aircraft such as the B-26 and P-38. This AT-9 at the National Museum of the USAF is one of only two examples that survive today.