The audio for the "jeep" at the beginning of the movie, later to be discovered as driven by his girlfriend, is clearly a V-8 engine. However, the truck being driven is a Suzuki Samurai J13, which features a 1.3 liter 4-cylinder motor.
When Dan is on the plane the flight attendant has on a USAF female uniform with one stripe. After the hijack attempt, the flight attendant's uniform has 2 stripes.