My advice: change seats.
I have an older p100 on Sprint. Similar to your device, I think. It is very picky, when it comes to power sources. First, if the power source isn't at least 2 amps, it's a non-starter. Even still, it's hit-and-miss.
My only success, has been the cigarette lighter plug from Samsung, and a Samsung-branded cable. Option two, is to take the AC adapter along for the ride, and plug it into an AC outlet...that is, if you were seated near one.
I can't think of anything that isn't overly complicated, easy enough to include in your carry-on, and less likely to prompt an inquisition from the TSA. Thank Samsung for making a device that isn't always easy to power externally.
How long is the flight? If you're domestic coast-to-coast, it should last the flight on a full charge. For overseas, you might just have to resort to charging in the terminal, during any layovers you might have.
Wish I had better news. If someone else has other suggestions, I'm all ears. too.