Every aircraft from the Wright Flyer to the B-787 has specific fasteners. Generally they were SAE spec. The standard of manufacture is better than auto hardware. National Aeronautical Standard (NAS), and Air Force (That's the way I learned it, some guys use Army) Navy (AN) are what's been accepted since before WW2. The English used Whitworth on several aircraft. I work on a French built aircraft that is 100% metric.
I have never seen a multi tool, although during the Barn Storming era, I think pilots and mechanics used whatever they could find. The odd ball wrenches I have, were fabricated out of used tools I found at the flea markets. The rest are off the Snap-On truck. You need quality tools because of the tight areas you have to work in. I did find a set of "Tuffy" screw drivers made in the 1930's that I like a lot. And I've been collecting all the Plomb "WF" stuff I can get.