because it is typically frowned upon to stab the bad guy....
The "glass" in an airliner window is not glass at all. In some cases it can even be stronger than parts of the fueselage. It's a polymer. Anyway, a shot to the glass would just make a neat little hole that would probably whistle through the double panes. You could plug it with your finger and have no fear of being sucked out. However, depending on altitude and airspeed, It could become a reasonably painfull exercise.
Explosive decompression without a b_mb is not feasible. However, it looks good in the movies.
I believe Calum did mean "shoot in a plane." Sky Marshals are armed with firearms inside a plane. If you catch a ride which has a destination of the USA or a Departure from The USA, there's a chance you have a Sky Marshal onboard, readuy to shoot the baddies if they act up. They are specially trained to do this and use typically special munitions.
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