When Jack knocks Mason out with the tranquilizer dart, he falls and Jack catches him, checking his pulse. However, Jack checks Mason's pulse with his thumb which isn't the correct way as the thumb has its own pulse.
The 747 that explodes over the Mojave Desert is stated to have flown direct from Berlin, where the assassin is supposed to have been hired. Berlin doesn't have an international airport, and won't until the new Berlin-Brandenburg International Airport is completed around 2010. The Schoenfeld, Tegel and Tempelhof airports that currently serve Berlin cannot accommodate a 747, and any flight from Berlin to the U.S. would have to connect from Frankfurt or Munich.