Foster's scooter business was in poor financial health during WWII, with Foster constantly looking for outside investors or a potential buyer. In the latter stages of the war, with victory looking more and more certain, Foster considered post-war options. He realized that he could not afford to expand the scooter business to take advantage of post-war opportunities.

Foster approached Richard Millar sometime in 1944. Until late 1942. Millar was the President of Vultee Aircraft. After resigning from from Vultee, Millar formed Avion, Inc. in March 1943. Avion built aircraft components for Douglas Aircraft. As the war started to wind down, the aircraft manufacturing companies like Avion knew that they would be looking at a drastic reduction in plane orders from the US government as soon as the war ended. Thus, the aircraft manufacturers were looking for alternative business opportunities. (Interesting side note - the post war Vespa and Fuji scooters were manufactured by the WWII aircraft manufacturing companies in Italy and Japan).

In December 1944 Foster and Millar agreed to a licensing arrangement that gave Avion worldwide rights for all applications and uses of Salsbury's vehicle patents. Given the importance of the new venture from a licensing revenue perspective, Foster and a few other key employees from the old Salsbury Corp agreed to work for Avion, Inc. Foster was in charge of sales and Marketing.

Sensing the end of the war was near, Millar and Avion aggressively set out to design and develop an ultra-modern designed scooter and a new 6 HP engine for use in post-war scooters and other applications.

Shortly after the war ended, in late October 1945, Avion Inc changed its name to Salsbury Motors. At the time of the name change, Don Carroll, President of Salsbury Motors, reported that the company expected sales in excess of $5,000,000 for 1946 on its product line of scooters, industrial trucks, package delivery cars, 6HP engines, and automatic transmissions and clutches.