It depends a lot on your equipment. Hvlp uses a lot of air. The old stuff seems to use less. However it’s not necessarily the compressor hp or volume but the reservoir size. I would suggest 5 hp, two stage, and 240 volts with 60-80 gallon tank. unless your done with air tools after this.
If you’re only going to paint one plane and that’s it,

then a smaller one will work.
I used a 3 hp single stage 20 gallon to paint several cars. It could barely keep up so some planning is required. The source tank pressure would get so low as I was finishing a coat the gun pressure would start dropping off.
Not saying it can’t be done, but paint, ready to shoot, is nearly 100$ a sprayable qt.

dont waste any
well gotta go, i have one more stripe to run err uh paint....
awesome 69 btw