A new Series ''A'' was started. It was a very critical one as it actually was to carry the company into the final design used. The Series "A" came out in 1940 and continued through World War II. The car had many new safety features and was one of the roomiest Checkers ever built.
There were many projects for future reference that had to be laid aside for the war effort. Once the war was over, Checker was ready to resume its manufacturing of taxicabs. Checker might have been way ahead of the times if the Model "B" series would have ever gotten off the ground. It was a rear engine, rear-wheel drive vehicle. There were only two built and were still being tested by the end of 1945. Not much information exists except they were not accepted well in the cab industry.
The Model ''C'' never got off the drawing boards, and was over-shadowed by the Model ''D''. This car took to the road in 1946 and looked like nothing else in the industry. There were big plans for this model. Fourteen different versions, to be exact. Some of them were to include a coupe, convertible, ambulance, pick-up, and panel trucks. The most unique feature was the front wheel drive and a cross-mounted six-cylinder engine. This whole project was kept fairly quiet and little was known about the car outside of Checker.
There were many problems, mostly with the front-wheel drive unit. The production would have had to be completely changed for one. There was a great need for new cabs after the war, and Checker felt the time involved for changeover would tax them too heavily. The decision was made to go back to the more conventional Model ''A''. They combined the pre-war car with the New Model "D" designs and came out with the Model A2 in February of 1947. This car stayed around until the end of 1955.
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.