Re: cars vs aircraft
To me, they are two very different types of work.
With aircraft, You need a detailed repair plan, lots of specialized (expensive) tools, the skills to work to tolerances of .001, and the ability to understand how all the parts are supposed to work together, especially when engineering drawings are flat out wrong. Small errors can lead to bigger problems that could ultimately kill people.

I see very little quality sheet metal repairs nowadays. Lots of hacks that really don’t care about legal repairs or quality workmanship.
With cars, major mods like chopping the top, enlarging wheel wells, and lowering the front end, require just a general idea, basic tools, and some prior experience. Tolerances of .125 are satisfactory because everything gets welded up and hammered into submission.

IMO, I wouldn't want a car mechanic crosstraining over to aircraft. He would have to unlearn much of his previous experience, which puts him at a greater disadvantage than someone who has no prior wrenching experience.
I had to retrain my brain when I first started restoring cars.

I used to reach for a digital caliper, when all I really needed was a ruler. I used to draw out detailed repairs, but now just rely on previous repair experiences. Working with steel cars is a whole lot easier than aluminum aircraft.
The nice thing about cars, is that I can get 5-8 times more visible work done per day than on aircraft, which is more satisfying.

With aircraft, I can spend many hours building a jig, modifying tools, making precise measurements, deciphering blueprints, fabricating parts, consulting with engineers, researching/ordering parts, cutting/fitting blank parts, laying out rivet patterns, drilling, countersinking, riveting, etc. With a car, drill out the spotwelds, remove a crumpled fender, clean up a flange, and weld a new fender in place.
