The best way to make a small fortune in aviation is to start with a large one. Yes, that's a joke, but there is a lot of painful truth behind it.
I know of more than a few pilots with plenty of hours, Airline Transport Pilot certificates and Flight Instructor certificates, Multi-Engine and Instrument certificates, and yet... they can't find work.
Aviation is a tough business with lots of regulation and competition. The regulatory enforcement is often spotty and can be rather arbitrary and capricious.
The hours are long, and for most, the pay is just a hair better than poverty wages (I'm not making that up).
But the view is fantastic, and the bragging rights are incredible. You can regale your tales of wild and crazy rides and ridiculous situations to friends and colleagues the world over. Mastery of a complex, high tech, airliner with incredibly weird and archaic modes of navigation and communications is a hoot. If you want adventure, become a "freight dog" pilot. There are many routes to fly in Cessna Caravans to pick up and deliver packages. They do it in all kinds of terrifyingly poor weather, at night, at airports that may be only a dirt strip in the middle of nowhere. It pays poorly, and it is not something to be done by the faint of heart. But if you want real adventure, it is out there.
I chose to go the route of private aviation. I got my private pilot license, and I got an instrument rating. I used to own an airplane. It was fun while I was able to afford it (before I got married and had kids). I really enjoyed being able to file flight plans on my own schedule. If the weather sucked, or the airplane's mechanical condition wasn't to my liking, I could stay on the ground or divert to another airport (if I was already en-route). And I could do this without wondering where my next meal would come from.
As for building aircraft, legal liability has changed the industry --and not for the better. Many respectable aircraft companies have gone out of business because they couldn't handle the frivolous law suits. There have been some notoriously awful court decisions that have put many companies into bankruptcy. Even laudable and innovative companies like Cirrus are having a hell of a time fending off law suits caused by stupid pilot tricks.
You COULD look at air traffic control. The stress can be extraordinary, but the pay ain't bad, and there will be significant demand for more air traffic controllers as many hired during the 1980s PATCO strike begin to retire.
As for design, well, read what I wrote about manufacturing.
The wonder is that there is still an aviation business at all. The airlines would like to squeeze everyone else out of the sky. Our Federal Government would love to oblige, but they keep running into that pesky problem: where is that next generation of pilots going to come from, and who is going to do all that specialized flying like freight carriers, firefighting, air ambulance work, and the like?
If you really don't care about making money until you are middle aged, then aviation is for you. Starting commercial pilot pay can be as low as $25k to $35k annually. People can make the same or better money managing a fast food joint. Keep a plan B for a secondary career handy because at some point you'll probably need it.
Good Luck!
