I'll add my two bits again to the Aircraft Engineers quoted in the article. Having maintained cabin pressurization systems while in the Navy and having performed at least 30 on-ground cabin pressurization tests, I can tell you that one dozen bullet holes in the skin of an airplane flying at 30K feet might make your ears pop, but that's all. The cabin pressurization system can easily handle keeping the cabin pressurized to a safe level.
Any hole smaller than a coffee cup will not significantly affect the pressurization systems on transport aircraft.
Knitebane
What if a round was to exit the fuselage, or maybe even take a chunk of metal off of the fuselage and further damage the plane. (like hit the intake side of an engine or throw some metal into it??) What about damage to electrical and/or hydraulic systems? What about some of the "disco era" planes we have in service? Are they strong enough to deal with these issues, metal fatigue and all?? Can you show me that bullets could do no more damage to a plane than a thumb size hole, every time? What about a nice tight group of 9 rounds fired in the same spot? Still nothing to worry about? There are types of ammo that can be used on plane to minimize these concerns, but how do you make sure everyone is using this ammo?
Look, I am a gun owner, and I have nothing against personal carry weapons. Quite the contrary. But you are asking me, as a passenger, to trust that this legal gun owner, packing a .50 Desert Eagle, is mentally competent to be on the plane traveling 500 Miles an hour at 35,000 feet. We don't do psych profiles on CCW tests. Are you prepared to trust everyone?
An ex-friend of mine in Oregon has a clean record, doesnt drink, or do drugs, and it scares the hell out of me to know this guy can carry a gun legally. He thinks hes in the old west or something. Ive seen the guy pull it because someone looked at him wrong. Sound fun at 30,000 feet? I totally respect his right to carry the gun, but that doesnt mean I feel safe around him. For that matter, I wont even go shooting with people I dont know or trust. If I see some moron waving his piece around on the range, I leave.
There are too many drunks, druggies, mentally unstable, pissed off at the world, etc in this world. Give them this much power and you have a quite a few dangerous possibilities.
Look at these terrorists. These people were our neighbors, doctors, flight students, etc. Would we have looked at them twice, under our Personal Airplane Carry (my title) law? Probably not. Even if you were to have a special Citizen Air Militia (my title) gun permit or something, these guys would have likely just gone and got one, passing without a hitch. Remember, these guys WANT to die. They are headed for paradise or whatever. Are we going to discriminate and disallowd Middle Eastern born Americans from carrying on planes?
I can say pretty surely that I dont want to be inside of a huge flying Tylenol with bullets hurling around inside of it- on the ground, or in the air.
Some of the Myths in the original posts are not Myths at all, they are REAL possibilities.