There's a reason professional auto painters don't use airless systems.
Boy that is a fact...I can't imagine what I would use one for unless I needed to paint my house (and then I would call a house painter.)
I bought a professional airless one time (a Binks industrial size) to apply dope to the blades of an experimental wind driven generator. This was, at the time, the largest wind driven generator in the world and it was designed & built by a joint venture between So Cal Edison & Bendix Energy Division. There were 3 blades each 94 feet long x 15 foot chord at the root x 4 foot chord at the tip, and each blade weighed 38,000 lbs. They were built of maple wood with open bays ahead of & behind the spar, and I covered them with the Razorback STC'd covering process which is essentially fiberglass cloth with butyrate dope. Spraying that much area with clear, silver, & white butyrate was too big a job to use the standard air spray guns. The airless gun put out so much material that it was all I could do to move fast enough to stay up with the gun. I used lots of thinner and retarder in the dope.
The finish was definitely nothing to write home about but it really wasn't too bad for what it was applied to. It was better than I expected from the airless sprayer.