Hacker News

All you need is a lithium laptop battery, pierce it, and you’ll have an unquenchable 2000°C fire very quickly.

That won't do it. Thanks to an accident back in the 90's (I think) when an entire cargo container full of laptop batteries burned up in the cargo hold, airplanes are built to resist these kinds of attacks now. There are also limits already on the size of batteries that you can bring on a flight, specifically to prevent someone from collecting a bunch of them and starting a fire. When planes crashes from a cargo fire, it's typically because the crew is unconscious or disoriented and unable to fly the airplane, despite it still being capable of flight.

TL:DR - the passengers can't bring enough batteries on a plane to take it down.