I usually cheat and just carry a stripped lower receiver if I'm not going to be carrying at the destination. I avoid going to NYC to the extent possible, too, though. The TSA people sometimes lol. The ones who handle guns also seem to be the best ones at the airport, and especially at Seattle, I like talking to them (someday when I get my manufacturer FFL I hope to show off some hot title II stuff there)
Tempted to start carrying an 80% lower, which is tech I ally not a firearm, to be even safer. Should still be able to get firearm service at the tsa for it.
There might be a market for cheap-as-hell injection molded lower receivers, not really good for any sort of shooting at all, to be sold to travelers so that they can be "technically" carrying a gun. It would be considered disposable so they could just crack it in two and throw it away at their destination (or perhaps have the shops that sell them also buy them back). I figure injection molded plastic would be sufficient, as plastic lowers have already been demonstrated.
It would only work to and from certain states of course. There are probably problems with selling and buying them back in airports, so disposal in some states may be a problem. If you are flying Kansas<->Vermont or similar it could probably be made to work though.
If I'm not mistaken, you can use a flare gun and get the same kind of service. This is a fine, nominally non lethal option if you still want the same assurance as a gun, but don't care for the whole lethal weapon aspect of it.
Probably just about the only instance where having a gun can actually thwart a corrupt government official.