You could probably do a search and find some good suggestions - I know I've posted these before, but, like Gandalf, I never mind explaining my brilliance more than once <img src="/images/graemlins/wink.gif" alt="" />

- Instead of relying on a single, easily breached perimeter, implement defense in depth. Put multiple obstacles in a hijacker's path, not just one. Our ancestors knew how to do this 1000 years ago; why the TSA can't figure it out is beyond me.

- Put First-class passengers at the back of the plane instead of the front. If I walk up to the ticket counter and say "I want a seat as close as possible to the flight crew cabin, and money is no object" they'll call for security. If I say "I want a seat in first class" I'm saying essentially the same thing, but the response will be "Yes, sir."

- Train all the flight attendants in hand-to-hand combat. (Air Canada has supposedly done so; maybe other airlines have as well.) Most El Al flight attendants are ex-military with h2h combat training.

- Arm the flight attendants with non-lethal (excuse me, "less lethal") tasers. Modify the tasers so they can't be fired if they're disconnected from the owner's belt, so terrorists can't steal them and use them (if you're really all that concerned about a terrorist trying to hijack a plane with a single-shot, non-lethal weapon that's already been fired, that is <img src="/images/graemlins/wink.gif" alt="" /> )

- Arm the pilots. (El Al refuses to comment on whether they do this, for security reasons.) Give the captain a sealed package containing an unloaded pistol and the first officer a sealed package containing the ammunition clip. If the seal is broken on either package at the end of the flight, the flight crew member responsible for it has to make a full report explaining how it happened.

- Have the pilots lock themselves inside the cabin before the start of every flight and don't allow them to unlock the cabin until the aircraft is at the gate and the passengers have disembarked. (Again, El Al does this.)

- Train the pilots in "anti-terrorist aerobatics". It's pretty hard to hijack a plane, or even maintain your dignity, when you're bouncing off the ceiling like Wile E. Coyote. (El Al claims they don't train their pilots in this manner. Yeah right! Tell that to Leila Khaled, who had this happen to her when she tried to hijack an El Al flight in September 1970.)

- Pass legislation to protect airlines and flight/cabin crew from lawsuits from passengers who didn't have their seat belts fastened when the pilot starts banging the hijackers against the ceiling, or depressurising the aircraft.

Not one of these measures would inconvenience the flying public one iota, unless they were confronted with an actual hijacking situation. (In which case, presumably, they wouldn't mind.)