Your key question is learning: "Is there a place to go to school to learn how to do this? "
As someone said starting at an automotive shop as an apprentice for OJT would be a great start. If you have a body shop nearby willing to take you on as an apprentice for OJT that would be good (and get paid of course). Keep in mind you will be spending a lot of time sweeping, sanding and doing the less than glamorous work at first. They are not going to let you mix paint and go into the spray booth and shoot paint on customer vehicles on day one. The "skill" of shooting paint is a bit of an art, but there are books and videos on it. However getting a good instructor and supervised practice is key. Who know you may be shooting paint in no time? Make sure they know you want to learn to paint but willing to work your way up. I would not go in and say I want to be your competition someday...
The other way is self teach yourself, buy compressor, hose, filter/water air separator, paint gun, make a spray booth and learn about paint products, buy some, and start shooting. Practice. There is no real degree in painting. I learned a lot watching hot rod shows (Detroit Muscle) where they showed how to paint cars. I also hung out at a Body Shop my friends dad owned when I was a kid in high school. I learned a little there. When I had my plane professionally painted back in the 90's I watched what and how they did it. Bottom line Prep and attention to detail and practice is key. Oh you WILL make mistakes or get runs or dirt in the paint. It happens. There are ways to recover.
If you are looking at it as a future business and being self employed, yes environmental considerations can be significant and more so in some states than others. For example I recall all the water you use to rinse off the paint stripper, etch, Alodine needs to be collected, put in barrels, removed as hazmat. That can't be cheap. In the old days they washed into the sewage system. To start up your own shop would be fairly large investment.
Labor - it is super labor intensive. So not to get into politics but many business are having a hard time hiring workers. I went to one paint shop and most of the workers did not speak English. The PREP work is a monster and can be very time consuming. I don't know of any one man shows except HOME BUILDERS
If you are going to make money you need volume. Working on older planes is a challenge. If they come beat up, needing sheet metal, cowl, fairing, wingtip, windscreen and window repair or replacement that is another issue. That will take skilled labor and someone with an A&P license. Speaking of A&P. If looking at an aviation career did you consider getting your A&P license? To be clear you do NOT need not need to have license or certificate to paint planes. However to work on the airframe or engine you do. A paint job on a plane besides repairs at minimum requires flight control removal and installation. The flight controls may need to be re-balanced after paint, That requires an A&P certificate. Doing airframe repair as part of an aircraft paint job can be a profit opportunity if you have the skill or skilled staff to do it. Many times older planes get new plexiglass or other parts that crack and get brittle over the years.
There is liability insurance as well if you are in business.
Personally I would not touch this kind of business with a 10 foot pole. I love painting in moderation, less the Prep work but it's fun to do ever 10 years. Ha ha. I had my 1993 RV-4 that was paint ready (never painted before, bare metal) cost me $6000 (they quoted $4000 and inflated the price after). At least it came out very nice. A quick look on-line I see numbers like $45,000 to paint a C182. I am painting my next project myself. Aircraft urethans are very expensive but no way am I paying that much to paint a plane.