I got a fire resistant bag that the battery resides in while in the airplane (copilot's seat pocket). The bag with the battery in it fits easily through the vent window. I also got a pair of these that I keep on the rear seat floor, just in case:
https://www.amazon.com/Fireproof-Cut-Re ... to_dp&th=1
I've still been removing the battery after every flight. Only takes a minute...
Lithium Battery pack in the airplane
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