Trivia: Producers of the movie were concerned that actual terrorists could use the information in the film to disrupt airport/airplane communications in real life. Most of the "sensitive" information in the film is not only wrong, it is purposely misleading to prevent terrorists from attempting what we see in the movie.
Trivia: The film is based on a book called "58 Minutes" by Walter Wager. In the book, it is the hero's young daughter, not his wife, that is on one of the planes.
Trivia: In March 1993, the Boeing 747-100 cargo aeroplane featured in this film (registration N473EV) was involved in an incident at Anchorage International Airport, Alaska, USA. Shortly after take-off the plane experienced troubles due to severe weather and the number two engine separated from the plane. Strangely enough, the number two engine is what "ingested" Major Grant after the encounter with McClane on the wing. The plane managed to land safely after this incident with no injuries.
Trivia: Renny Harlin, the film's director, is from Finland and puts something Finnish in each film he directs. At the end of Die Hard 2 Jean Sibelius' Finlandia plays.
Trivia: The majority of the airport shots in this film were not filmed at Dulles, it is Stapleton Airport in Denver.
Trivia: When being played on basic cable or regular TV, John McClane's catchphrase "Yippee ki yay, mother fucker!" is sometimes oddly redubbed as "Yippee ki yay, Mr. Falcon!" Falcon is the call sign for General Esperanza's original flight, which half explains the odd wording.
Trivia: When the older lady is showing off her taser in the beginning of the film she is holding a magazine. On the back of the magazine is an advertisement for Lethal Weapon. Joel Silver, who produced Lethal Weapon, also produced this film. (00:05:36)
Trivia: The fictional country that General Esperanza is from is Val Verde, which was the same country where Arius had been a dictator in the 1985 film, Commando, also produced by Joel Silver. (00:02:30)
Suggested correction: The terrorists in the film planned extensively for this operation, but the storm occurring may have just been a coincidence for them. They may also have had the plan waiting for a perfect opportunity, like a snowstorm. In the beginning of the movie, there's a news story on while the Colonel is exercising nude. The story says Esperanza's extradition has been long and drawn out, until a phone call from..." and he cuts the TV off. Given his connections, Colonel Stewart may well have been able to arrange a State Department call the week of a predicted snow storm. Esperanza's adherents may also have been able. Another scenario they may have had is to take the Air Traffic Controllers hostage (as they did) and have the other aircraft diverted for a supposed emergency, but the snowstorm worked out. Whatever the case, that element of the plot is an interesting discussion, not a mistake.
If the storm hadn't hit the pilots of the stranded airliners could easily have diverted to any one of half a dozen alternates, including a nearby Air Force base. They could do this without consulting or even contacting air traffic control. The whole plot falls apart from there - no hostages, no leverage, and who cares what happens to the people on the Esperanza's plane? They'd have it shot down.
The snowstorm was not part of the plan. Early on when the group of terrorists is sitting around the table about to exchange the package, Cochran is listening to a weather report and states that a huge storm is approaching, which makes the other men smile and one of them responds "God loves the infantry." The terrorists could still crash planes without the snow storm because they could impersonate the tower. The planes that are circling overhead are the planes that didn't have enough fuel to be diverted to another airport and that has nothing to do with a snow storm. The blizzard was simply fortuitous for the terrorists.
BaconIsMyBFF
The airliners we see could easily glide to any one of seven nearby airports from the airspace over Dulles, let alone fly there when fuel began running low.
That is a separate issue (and is indeed a mistake in the film) that doesn't really have anything to do with the blizzard. This film acts as if Baltimore Washington International or Richmond International Airport don't exist.
BaconIsMyBFF
And since they do, it is both a plot hole and a factual error. If they had called their fictional airport Springfield International, fine, but they didn't. They identified it as Dulles International which is within easy flying - or gliding - time to half a dozen other airports.
This is possible that other airports were closed due to bad weather.
Which necessitates the terrorists knowing that! They had to know the storm was coming for their plan to work. The stranded airlines could easily have diverted to an alternative even if that meant gliding, and they could do so without consulting air traffic control.
The terrorist obviously knew that. They are very arrogant and planned everything very accurately. They knew that other airports are closed because of the bad weather.
The airports were closed AFTER Esperanza's flight took off. The storm is an essential part of the terrorist's plans. Storms like the one we see can can diminish very rapidly or veer away from their original course (I have seen both happen) and cannot, ever, be counted on to the meticulous extent the terrorists do.