Kinner Airster airframe and it was manufactured as the Crown B-3 between 1930 and 1933. 1932 would mark several major changes for the company. As part of his taking over day-to-day operations of Crown from his father, MM Brockway introduced a ground-breaking school bus body; elements of its design would change school bus design forever. To improve forward visibility, the new bus was a cab-forward design, with the driver sitting next to the engine and radiator. To improve safety, the bus was designed with an integral chassis; the windows were mesh-reinforced safety glass. Alongside the standard braking system, the bus also was equipped with two backup braking systems. In 1935, the cab-forward school bus was updated and dubbed the Crown Supercoach. For 1937, to increase seating capacity to 79 passengers, Crown produced its first mid-engine Supercoach; the bus came with a Hall-Scott gasoline engine. In 1939, Crown acquired Moreland Motor Truck Company; as part of the acquisition, Crown moved to a larger factory in Los Angeles. Additionally, the Supercoach was changed from a mid-engine to a rear-engine configuration for 1940. During World War II, the production of Crown Coach was diverted towards military use; most bodies produced by the company were fire engine bodies for four-wheel drive truck chassis. Following the war, the company returned to bus production, beginning design work on the 1948 Supercoach. As a side project, engineers at the company designed an all-new cabover fire engine, using the mid-engine chassis of the Supercoach bus. The first Crown Firecoach prototype was completed in 1951, after two years of design work. Alongside the initial pumper design, Crown developed several configurations of the Firecoach, including water tenders, tiller and ladder trucks, and quints (TeleSquirts). In the United States during the years immediately following World War II, population growth of suburbs expanded, fueled by the post-war baby boom. As that segment of the population entered school, demand for new schools (and school buses to transport their students) rapidly rose. In 1946, Crown began development on a new mid-engine Supercoach. Heavily influenced by motorcoach design, Crown intended it primarily for school bus use. Introduced in 1949, the all-new Supercoach used unit-body construction with high-strength steel in place of a separate chassis; to combat corrosion, all body panels were aluminum. To prove the durability of the Supercoach to potential customers, Crown offered the Supercoach with a 20-year/100,000 mile warranty for the body. 1950–1980: