Revealing mistake: When the huge alien ship settles over the White House there is an exterior wideshot of the grounds. At the bottom of this shot it's funny how there are many tourists - adults and children, just milling around in front of the gate and across the street with a van driving along between the two sides, and not one has any sort of reaction to the alien ship. This real shot of the White House (some shots had smaller-scale models) had the CG ship edited in during post production. (Visible on fullscreen DVD.)
Continuity mistake: When the President holds his frightened daughter, in the shot after the alien craft creates a shadow over the White House, there are photographs and a bust of Lincoln on the table beside the President - the view of the photos is not blocked by anything. In the very next close-up of the photos, things differ, such as a large framed photo of the President with the Dalai Lama that appears out of nowhere, between the photo of the First Lady and the photo of the Pope.
Factual error: In any explosion the shock-wave will travel ahead of any debris thrown by the shock-wave. During the attack scenes there are numerous cases of debris, particularly vehicles, travelling and landing in still air ahead of the arrival of the shock-wave.
Other mistake: When they're shooting the nuclear-bomb at the space craft for the first time (when it fails due to the shield on the alien space craft), you see that the airplane shooting the missile is breaking off to the left just after it's fired the missile. On the radar a few seconds later you see the airplane breaking off to the right. As if the radar displayed a mirrored view.
Visible crew/equipment: At Area 51's main research facility, Dr. Okun walks up to greet President Whitmore and as his assistant, Dr. Isaacs walks up behind him, the green actor's mark is visible on the floor - he even glances down at it. (Only visible on fullscreen DVD.)
Visible crew/equipment: At the containment lab, just before Dr. Okun unlocks "the vault", three actors' marks are visible. One mark is at the top of the ramp and the other two are visible just past the ramp. (Only visible on fullscreen DVD.)
Continuity mistake: When Jasmine grabs Dylan out of the car, his sneakers are white/black with black laces, but when she is kicking the maintenance door, his sneakers are white with white laces, then it switches again in following shots.
Visible crew/equipment: At the Area 51 lab, when President Whitmore is down on the ground in pain, in the shot from inside the lab facing the lab's outer hall, the alien costume only reaches just above the crewmember's waist - the costume straps attached to his pants are visible, as well as his arm. (Only visible on fullscreen DVD.)
Factual error: The US Bank Tower's placement in between Citi Group and Melon Bank is inconsistent from its real life position. Citi Group should be roughly directly parallel, not off-center at an angle.
Continuity mistake: When Jasmine sees the approaching fireball she grabs Dylan from the car and begins to run. In the shot from behind, there are double-yellow lines on the road at her feet reaching into the distance, but in the shot facing her the lines have vanished, though she did not change lanes.
Visible crew/equipment: When President Whitmore, General Grey and the rest return to the containment lab to see the live alien, Major Mitchell stands directly in front of the smoke filled lab and the camera equipment/crew are visible in the reflection on the glass. President Whitmore, General Grey and a few others are supposed to be the only ones in front of the three aliens' liquid chambers. (Only visible on fullscreen DVD.)
Continuity mistake: In the briefing scene at El Toro prior to the first counter-offensive, Lt. Colonel Watson, the briefing officer, has silver oak leaves on his collar (Marine Lieutenant Colonel). A few scenes later, when El Toro is under attack, Lt. Colonel Watson is shown again, but has been demoted two grades and has two silver bars on his collars (Marine Captain).
Visible crew/equipment: After Steven and David return, when President Whitmore walks over to David reflections of the reflector screen are visible on the President's sunglasses.
Continuity mistake: At the White House, after the President says good morning to Connie and walks past her, she stands up then places the two folded sections of USA Today in her left hand - with the headline section covered, as she holds her briefcase in her right hand. Next shot from behind, she is now holding a section in her right hand with the briefcase, as she reads from the headline section held in her left hand.
Continuity mistake: When David walks into his office, with Marty, he sits down at his desk, and the water bottle is in front of the computer monitor, to the left of the keyboard. In the next shot, when he picks up the bottle it has moved to the right side of the keyboard.
Continuity mistake: When President Whitmore boards the chopper and then Air Force One, he wears a white shirt with both thin and thick stripes. The stripes on his shirt collar constantly change, and nowhere is it more noticeable than when they arrive at Area 51. It varies between only one thick stripe, which changes from the top of the collar to the bottom, or two or more thick stripes, all surrounded by thin stripes. Wardrobe Dept bought identical shirts for the actor to wear, but the collar stripes just don't match up between scenes.
Visible crew/equipment: When the alien is inflicting pain upon President Whitmore telepathically, in the shot from inside the lab facing the outer hall, through the glass, General Grey's mark is visible on the floor. (Only visible on fullscreen DVD.)
Visible crew/equipment: After the President and the rest return to the containment lab to see the live alien, when Major Mitchell is standing in front of the smoke filled lab, a piece of equipment is seen moving about at the bottom of the screen. (Only visible on fullscreen DVD.)
Visible crew/equipment: After President Whitmore decides to go ahead with David's plan for the virus, he, Connie and Grey are walking when the President pushes Nimzicki up against a desk. Just before they reach that desk, the actor's mark is visible on the floor, precisely where the President stops before he fires Nimzicki. (Only visible on fullscreen DVD.)
Continuity mistake: Julius and David are driving in the Plymouth and when they reach DC, the car's rearview mirror is visible from the back, but in the next close-up as they pull up in front of the White House gate, the rearview mirror has vanished.
Answer: In the book of the same name, this man is called "Pig". He was a test pilot during the Vietnam War. He played a crucial role in training the new pilots.