Boston Logan airport has certain benches dedicated to power charging, and for the most part they all have two power sockets and two dedicated USB charging ports.
I've also seen dedicated cell phone charging stations at other airports that have USB charging ports alone.
USB-only chargers in airports definitely exist, and are sometimes fought over in busier airports.
Newer/remodeled hotels and airports are full of these things now. They don't exactly jump out at you, they would be easy enough to miss.
AFAIK these things are just dumb voltage sources, they don't have any USB controllers that could be hacked. At least, the ones you and I can buy don't. But there isn't, in principle, any reason why they couldn't have such controllers, either.
Dreamliner has USB sockets for charging. I think you can also load media over them, but it might be iPod/iPhone only. (That's lame, but he Dreamliner has the best in-flight entertainment system I've ever seen; I usually shut them off, but they had enough Pink Floyd in the on-demand library for take-off and landing, which was nice.)
Last time that I flew SouthWest, they had specific "charging seats" (that had power outlets and USB sockets for charging) in their terminal. (Note: this was maybe 2008 ~ 2009)
