"9/11 was 4 flights out of 20,000. So we can't draw any conclusions?"
Not in this inaccurate context you are displaying.
9/11 should be viewed not against 20,000 flights, it should be viewed against a full decade of flights.
Basically, 4 flights out of several million.
you see, thats the problem. beauractats worry only about the bottom line...always with the nonsensical numbers and 'facts' and odds...etcc. blah. It's also been said by particular airlines that it's more cost efficient for them to have an airplane crash and the fam's of everyone aboard sue, than to spend and update to fix their flying coffins...no one is concerned about numbers, its the fact of killing americans no one likes. can you just be ok with the fact that some are concerned about that and not so much about facts and figures.