Aircraft Safety

If someone tries to hijack your aircraft, attack them! Don't wait to see if they are going to negotiate or crash in to a building. If they are suicide bombers, whether they are religious fanatics or just mentally ill, you won't get enough warning of their intention to act later. Your best chance is in the first couple of seconds, don't wait to see if armed air marshals can stop them. If you have a group of suicidal fanatics some will simply jump on the armed guards and give the others the vital few seconds they need to grab the guns, then you will have armed hijackers to deal with instead of unarmed ones! The best way to protect airplanes from suicide hijackers is to make the cockpit secure. Putting guns into the situation only increases the danger.

Incidentally modern passenger planes have the cabin pressure automatically controlled. Without going in to the technical detail, a controlled amount of air is brought in through the engine and a controlled amount is taken out elsewhere so that there is a certain amount of fresh air. So a bullet hole in the fusilage will not cause decompression.