In 1956 the A8 was introduced and very well received. It was very different from all previous Checker designs. The I-beam front axles were replaced by coil suspension with ball joints. The chassis was redesigned for added durability and additional front-end protection. Power steering, power brakes, and automatic transmissions were available as options. The glass area was increased to give the drive better vision. This basic design is the one that remained, except for a few minor changes, until the end, in 1982.

In October of 1958 the A9 was unveiled. These were the stretch models commonly called the "Aerobus." They came in two models, nine and twelve passenger vehicles on 154-1/2 and 189-inch wheelbases, respectively. The vehicle was in immediate demand all over the world for airport and motel-hotel use. This version was not a taxi stretched out, but a completely new vehicle with extremely sturdy box frame members. Each passenger seat had it's own door, and the rear luggage compartment had stainless steel strips that held bags firm so they would not scrape the windows. The nine-passenger stayed in production until 1969 and the 12-passenger stayed in production until 1974.

The private passenger car came on the scene in 1960 and was called the "Superba". Two models were introduced, the four-door sedan and the station wagon (like the one owned by founders Bev & Don McHenry). Each model came in two series, the regular and the Special. The latter one had side script on the body and the same additional trim along with better decor inside. The difference in price was around $100. The sedan held eight passengers and the station wagon held six. The wagon's rear seat folded down to form a very large cargo area. In fact you could haul a sheet of 4' by 8' plywood with the tailgate closed.