DarkBronzePlant

I assumed that it was just a diversion. Get the whole CTU squad chasing the plane, and meanwhile, Marie slips out with a car and the real bomb. Of course, if CTU was to actually focus so much on the plane that they forget to secure the rest of the airfield, that would be a little iffy as well, but at least plausible.

My problem with that scene was that, at that point, they'd have F-16s, and probably some Apache helicopters, circling the airfield. If the plane was on the runway, they'd swooped in and shot out the engine, or maybe blown a big hole in the runway. But again, that's not a show-stopping issue.