[Professional Engineer]

Aww shucks

[EQAndyBuzz]

There should not be armed guards on a plane. There should be no way that someone can get on a plane with a weapon in the first place.

Put a special forces person or someone fluent in hand to hand combat on the plane instead. Tighten security measures before check in. Make sure that no one can get into the cockpit. Screw it if someone is being inconvenienced by delays.

Finally, hold the country that the flight originated in fully responsible for the protection of the passengers.