Some airlines have car-lighter sockets under the seats. Some have wall-plugs on the back of the seat in front of you. Things improve on new birds. But yeah,

Some airlines have car-lighter sockets under the seats. Some have wall-plugs on the back of the seat in front of you. Things improve on new birds. But yeah, have multiple batteries if you gotta run it for a while. But have the plugs and the air/car charger just in case - although the plane might be 15V vs. 12V for the car. You might be able to go to your airlines website and look at the inflight entertainment or technology entries (and the seat maps for the specific models/planes) to see what's what.