Hawaiian Airlines now provides a USB outlet on the back of the seat in front of you so you can keep your mobile phone and small tablet devices powered up while in flight.
It used to be that if you ran out of juice while in the air, you were out of luck. Not any more.
Unfortunately, it doesn't charge iPads or other large tablet devices, so I was out of luck. Still, I was conservative in my game playing, so I had a bit of juice left when we landed.
While waiting for our flight back to Hawaii a couple of weeks later, I bought a neat rechargable battery with all the necessary plugs and cables from a vending machine in the airport. I'll tell you about that at a later date.