Errors in geography
In the scene with the kids visiting the TRACON where they all work, a plane departs that doesn't call the controller and this ends up causing a near collision. The airport image on the radar scope is of Newark Liberty International (you can tell by the two lines running essentially North/South that represent the two parallel N/S runways 4L/22R and 4R/22L). However, when the scene changes to the actual plane on an actual runway departing North, you see it pass over simply the number "4" and then immediately over water. This can only be LaGuardia Airport as it is the only airport of the three in New York (JFK, LaGuardia, Newark) that has only one N/S runway (4/22 - both Newark and Kennedy have 4L/22R and 4R/22L and are marked with the "R" and "L" on them) and has water immediately to the north of it.
During the bomb threat, Ross phones Sparta Airlines' base operations in Greensboro, South Carolina. There is no Greensboro in South Carolina - Greensboro is in North Carolina. However, there is a Greenville in South Carolina, which shares its airport with Spartanburg, South Carolina, which may be origin of the name "Sparta Airlines".