I always have PPF put on my cars and I'm a complete believer. Generally, just the front 1/3, which protects against rock chips and allows bugs to pretty much just wipe off with a wet microfiber. I've used 3M and Xpel, and most recently on a new Nissan Z, I had it custom cut and installed at the local Ford dealer...cost was about $1000. Typical life of the stuff is about 10 years before it demonstrates cloudiness or maybe some yellowing if you buy the cheap stuff, and 10 years is exactly what I got on my last sports car. The film was a little cloudy and stained but the paint beneath was pristine when I removed it and buffed a little. There were multiple rock gouges in the film but no paint damage underneath. Watching the install going around those multiple compound curves of the car, I was struck by what a PITA it would be for me. On an airplane, however, I think that the install would be within the reach of a DIY'er with a little practice. The 3M stuff is expensive, the thicker even more so, but you can buy larger sheets of the stuff.
Frankly, I can't imagine that a PPF install on an airplane would be worth the very high expense and the weight. In that install, it's primary value IMHO would be UV and oxidation protection for the paint, and I think there are cheaper solutions for mitigating that, maybe including a hangar. Rock chips IME just are not an issue except wheel pants. Leading edges take the brunt of the bugs and some good clear coat and diligent Rejex (or similar) application handles that issue. I don't think carnauba would be durable enough. I haven't availed myself of ceramic applications on cars...my impression is that it is just not worth the expense given their relative lack of longevity and high expense.
Personally, assuming you have a reasonable clear coat application, I'd stick with Rejex or a silicone-based wax.
