Way back in the days of a siphon feed gun (devilbiss JGA) I painted a couple of cars with a portable compressor. It has (I still have it) a 5 HP briggs gas engine and a 20 gallon tank.
Painting a whole car was interesting. Paint for a few minutes...wait on the compressor (repeat, repeat, repeat-you get the idea). It was really hard on the compressor I am sure, but it worked.
I now have a 60 gallon black max (upright), but I wish it were two stage. Still not enough air for running a DA continuously.