I presume this film was made before 9/11. I can't remember when I got my US copy but the time it's taken to get a UK release probably reflects the fact that it would have seemed in very bad taste back in 2001 when it could have been released.
A very good opening as a guy burns the midnight oil in his office while the relaxed passengers of an airliner prepare for a landing in Denver. As soon as you see that the pilots have lost control of the plane you know what to expect but the sequence is quite well done as the office worker turns just in time to see the nose of the plane at his window.
The "Federal Agent" referred to in the synopsis is actually a computer geek working for the Federal Aviation Authority. Pursuing an investigation into someone hacking into aircraft computers, which his superiors have told him to forget, he manages to get aboard the next target. Aided by a stewardess, played by Terminator 3's Kristanna Loken, he tries to regain control of the plane as it heads towards the biggest disaster in history.
Some edge of seat stuff and a romance that is never allowed to get in the way of doing his job while getting the plane down safely if not exacly intact. The passengers are taken straight from standard disaster movie specifications, but still do a reasonable job of making you care. A final sting in the tail, which allows for a misleading trailer, brings things nicely to a close.
You have to suspend disbelief a bit as characters recover too quickly from injuries when the scriptwriter forgets how serious he made them out to be, but otherwise I found it quite a satisfying film.