Plane Chassis Grounding
An evolving answer

Go study Faraday cages. The plane's metal air-frame acts like a Faraday cage. If that doesn't provide an answer, please explain why it doesn't. Maybe draw a picture so that it's clearer.


  SO from what I've read about Faraday, I understand that it will take
  the excess amount of charge, redistribute it equally on the external
  layer of the cage, however it still doesn't explain what happens to
  this new amount of charge added, does it stays here forever?


The charge remains unless it is removed. Charge is electrons so they remain unless taken away.


  This is starting to pinpoint my problem, let's say the plane gets hit
  by many lightning and accumulate the charge, is there a limit to the
  amount of charge it can accumulate? What will happens if we striker in
  indefinitely? There must be a limit to how much charges can be
  accumulated in the faraday cage?


It's voltage would rise until it became the next source of lightning! 


  oh wow I see! Thx a lot. But some kind of faraday cage must stop
  charging, like a car with air friction? It probably can't build up
  charge forever?


Like I said, it eventually produces a lightning strike to earth or some other large mass nearby that didn’t have the same charge on it. 


  nice!! thx a lot for your time sir. would sure be curious to see a
  plane discharge like that!