Statistically, even counting the lost life from the terrorists, flying is still the safest way to travel.
Additionally, with all the "increased security" going on everywhere, I'd doubt much would get through.
Lastly, I honestly doubt we'll see the same kind of attempted plane takeover anytime soon. One thing the terrorists did, which they prolly didn't expect, was make the life of any future plane terrorists much harder.
You see, a year ago, if some terrorists tried to take over the plane, the passengers would sit by quietly, expecting that if they don't cause problems, they'll eventually be set free. People no longer have that expectation. Anyone who makes any attempt at hijacking a plane in the future is going to have every passenger on that plane attacking them. When you expect to get out of a situation safely if you don't cause trouble, you aren't willing to take much risk. When you expect to die no matter what you do, attacking a terrorist armed with a box cutter doesn't seem like such a crazy idea anymore.
And, when you consider that your average passenger plane has upwards of 100 people on it, even if only half them are able bodied enough to act, that still leaves the terrorists with the odds 10 to 1 against them. You'd have to be more than just ready to die for your beliefs to take on those odds, you'd have to be really freakin' stupid, too.
I really doubt there will be many future airplane hijackings, and I doubt even more there will be any successful ones.