Lets assume the worst and say that terrorists seize 10 Planes that day (a very, very unlikely event). Did you know that at any given time there are 4000-6000 planes in the air and that more than 1400 of these are commercial passenger flights? That means that even if you happen to be boarding a plane during the time when the terrorist seized their airplanes, your odds would be .7 out of 100 of being on one of the unlucky planes. The actual odds are even lower because of the possibility of the seizing cargo planes and the fact that you have a very good chance of choosing a flight time beofre or fter that of the terroists.