I once looked up my own WW2 Jeep's registration number, trying to find a photo of it I had posted and had forgotten the site. I found three sites with photos of my own Jeep, none of which I had taken. One was a photo with me sitting in it, in a parade. Yes, it's an odd feeling, but they were all enthusiast or hobby sites, so they were done in a way that made perfect sense to me.
It does irritate me greatly that this guy feels some kind of right to be able to demand you remove a photo taken legally. If he'd been at a public event and you took a photo of his face (think paparazzi), you can do anything you want with it, what's the difference with his airplane? I probably would have ended my note to him with, "…and the horse you rode in on," and called it good. But that's just me.
If you have never seen it before, here's a good guide on photographer's rights. As with all things legal, most folks repeat incorrect info they've heard over the years and it often runs against what the legal standard really is:
http://www.krages.com/phoright.htm I might just get a copy of this book as I've been rousted by railroad officials when taking photos of trains from public areas like parks and sidewalks overlooking tracks. I've told the RR cops to go stick it when they ask me who I am or what I'm doing. His isn't because I'm one of those, "I know my rights" kind of people, but I don't feel I must justify myself to anyone when I'm being legal. Sadly, within the last 20 years or so, we've seen an increase of "self appointed" types who feel their authority extends to everywhere and everything. Being on the receiving end of folks like this in the past, I no longer recognize anyone other than legally appointed representatives as having any authority in anything I do. In other words, if you're a cop or a guard (and I'm on your property), then I'll listen to you. Otherwise, I'll tell you where to stick it.