One of the outstanding pioneers of aviation, William Powell Lear, who had finished only the eighth grade. William Lear is best known for designing and building the Learjet, the world's first cheap, fast, mass produced business jet. He is also credited with inventing the car radio, the eight track stereo tape player and cartridges, the autopilot for jet aircraft, the navigational radio, and the radio direction finder for general aviation aircraft. Lear founded and sold a number of different businesses and also held more than 150 patents.