Hello, currently I think there is no way of doing that. I read some other users also wanting the same thing, at least an option to be able to choose if we want to charge also or just connect. Maybe there is a setting on your phone which can help you with that, like in Developer Options(for Android) you can choose what the USB can do, like charge only, or data transfer only. So its worth giving it a try.
Also the other thing you can do is to just have your phone charged to 100% before you go fly, then It will just keep it there at 100 I guess - even though it's still charging. This should not be an issue though.