Numerous continuity errors, for example in the beginning of the film the fighter-planes change type several times between shots. They start off as F/A-18 Hornets, then suddenly change to F-22 Raptors in the cockpit shots of the pilots, and later they're F-16 Falcons instead.
When Bill, Julia and Nelson are departing in the Cessna, on the ground it is a tail-dragger with a small wheel under the tail. But after take off it is a tricycle gear, with a wheel under the nose.
During the final attack, the number and formation of the aircraft changes from shot to shot - 9 to 6 to 4 to 1.
Divya flies the helicopter with both hands on the cyclic, which non-helicopter pilots might refer to as the stick. Conventional helicopters are flown with two hand controls, a left-hand collective for power, which Divya would have definitely needed to climb, and the right-hand cyclic for lateral control.
We hear radio conversations making repeated reference to the "flight deck", and we then see aircraft flying over the sea, but the ship that is shown is a warship with large deck guns, and not an aircraft carrier.
When they show the AWAC, the cockpit is of a bell helicopter, when in fact the AWAC is like any other commercial plane.
About 34 minutes into the film B-1B bombers are in formation to bomb the glacier. When the piolts speak it shows a 1-man fghter cockpit. The B-1B front cabin seats two.
The glacier is stated at travelling at 200mph at the time the helicopters deliver the troops and explosives. However the the prime lifter of the US forces is the UH-60 Black Hawk which has a top speed in level flight of approx 160Knots/184mph.(And other transport types are even slower). Even allowing for generalised figures it would be impossible for such a helicopter, or indeed any of the other helicopters of the US to land troops, and certainly not carrying under-slung loads which would mean significantly lower speeds.
When Nelson says "Those are F-16's going in" the aircraft shots switch from an F-15 to an F-18.
When Bill crashes his car and turns it over on its roof, you can clearly see that they use a ramp.
Many streets have obviously been cleared of snow. There wouldn't have been time to do this.
When the Katie and Nick are going out of the tunnel of New Jersey, the camera that simulates "their going out" is inside a car with snow over the glass.
The exterior views of the helicopter (artificially inserted, no settlement of landing gear into the snow, no rotor wash blowing tents pitched within a rotor diameter of the helicopter) show what appears to be an AgustaWestland AW101 (Merlin), a medium-lift helicopter. The cockpit view is that of a much smaller, light observation helicopter, such as the Bell 206 JetRanger.
It is freezing cold and people are complaining and shivering...with their coats open and shirt collars unbuttoned.
During the last aircraft attack, the F-16s shown are the USAF Thunderbirds, which are stationed @Nellis AFB, outside of Las Vegas, NV, and would also take several hours to make them combat ready. The F-18s shown are the US NavyBlue Angel's, which are stationed in Pensacola, FL.
Bangor Maine isn't on the coast. It's about 40 miles inland from the coast
The glacier was traveling at 200 mph against the ocean currents. Even assuming all the oceans currents instantaneously reversed direction, the glacier should have collided with Nova Scotia, Newfoundland & Labrador before ever hitting Maine.
Massachusetts sticks out from the coast of the United States. The "glacier" would have needed to make a hard left, then a hard right to hit New York City while avoiding Boston & Connecticut.
When they show the shot of Boston, after the B1-B, the people outside froze instantly, but the main characters haven't even though they are north of the iceberg.