Conceived by American Jet Industries. Mixed power, with a turboprop in the nose and jet engine in the tail. Flew in January 1978. Became the Grumman American Hustler 400 following AJI's takeover of Grumman American in 1978. By May 1981, N400AJ had amassed only 30 hours. It was replaced that month by an improved version, the Grumman American Hustler 500. Hustler project cancelled completely later that year.

Full-scale mock-up of the American Jet Industries Hustler. The prototype of the Hustler 400 made its first flight on 11 January 1978.