Kang uses the term "Sea of Japan". Koreans (both North and South) use the term "East Sea", as they find the term "Sea of Japan" offensive. A hardcore Korean nationalist like Kang would use the term "East Sea" as well.
Secret Service Director Jacobs says activating the ICBM self-destruction program would make the U.S. vulnerable to nuclear missile attack. Aside from the fact that the self-destruct program does not exist, the ICBM, SLBM, and bomber force only deters such an attack. America does not have a deployed, large-scale missile defense system, and did not pursue one under the ABM Treaty with the USSR.
After Banning and Connor emerge from between the walls, Banning shoots his pistol to slide lock. He immediately drops the pistol and draws another. In the next shot he is still holding the empty pistol.
After the two terrorists bomb the two stations with R.P.G.s, terrorists and Secret Service agents fight near the driveway. In an overhead shot of the explosion, as the smoke clears, no one is near the black armored cars.
(at around 1h 27 mins) Banning is seen with what looks like a Motorola Bluetooth. Later, (at around 1h 34 mins), he is seen with what looks like a Plantronics-type Bluetooth with a long-boom. A few minutes later he is back to the Motorola.
The message shown when Kang ends a call to the command center is different every time. The first time, it says "P.E.O.C. Terminated Communication", the second time it's "Communication Terminated", and the third time, "Communication Terminated By The White House: P.E.O.C.".
The intruding Gunship shoots down both planes sent to intercept it. In real life, to avoid incidents like that, one interceptor establishes visual contact with the intruder and flies beside him. The other plane flies behind the intruder to shoot him down if the first interceptor experiences hostile action.
It makes no sense for the Chairman of the Joints Chiefs of Staff to have a nuclear missile self-destruct code. The Chain of command for employment of nuclear forces consists The President, the Secretary of Defense, and the Commander of U.S. Strategic Command (stationed at Offutt AFB, Nebraska). Plus, nuclear missiles have no self-destruct capability.
In the film, the Presidential limousine has standard doors and windows, with no armor plating or ballistic glass. In real life, the Presidential limousine is so heavily armored, the Secret Service calls it "The Beast."
The South Korean prime minister is mainly a ceremonial position, concerned with domestic affairs. Meetings with high-profile foreign heads of state, such as the U.S. president, would be handled by the South Korean president.
All references to NORAD are incorrect. NORAD (the North American Aerospace Defense Command) is a combined command with the mission of detecting and reporting attack on North America. It possesses no nuclear weapons. Strategic Command is responsible for strategic attack, and the ICBMs would be operated by the Air Force Global Strike Command.
Even if an AC-130 could be modified with 4 miniguns (2 on each side) to fire upon the F-22s flying side by side, the same AC-130 with the same loadout could not fire directly perpendicular to the AC-130's flight trajectory. To fire the miniguns on civilians and law enforcement, the pilot would have to roll the plane to at least a 45-degree angle, making 2 miniguns inoperable.
When the AC-130 is intercepted by two USAF aircraft right before the attack, they are both shot down after the AC-130 deploys cannon on both flanks. In real life, all AC-130 variants have cannon only on the left side. The aircraft attacks by performing a left-hand pylon turn centered on its target. It's intended as an air-to-ground weapon system, not air-to-air.
When the President's son is playing Uncharted 3: Drake's Deception on his Playstation 3, the controller is turned off. When the TV is turned off he hits the power button the light on the controller comes on and you hear the "beep" as the PS3 powers up.
The goof items below may give away important plot points.
When Banning discovers the President's son in the walls, the kid is hiding because he knows people are after him. Yet when the glare of a flashlight attached to a gun blinds him in the face, he jumps into that person's arms, even though he has no idea who is holding the gun.
During the attack, the Speaker of the House is "officially" placed under Secret Service protection because the President and Vice President are incapacitated. The Speaker of the House already qualifies for such protection.