Went through some of my grandfather’s personal effects and documents this evening. He and his brothers operated a gas station / mechanic’s from around 1932-1942. As you can see from the photo below, when he / they got drafted in 42, they had to sell it. I imagine there were a lot of signs like this at that time.
So, he was an auto mechanic from 32-42, then an aircraft mechanic from 42-45 (23rd FG, China), then an auto mechanic with NACA near DC for most of 45, then when he became a civilian, he went right back to being an automobile mechanic. After the war he married and raised two children.