For her more physically demanding scenes, Melissa Leo did step-ups on an apple box in between takes, to keep her heart-rate up. She also wore a brown wig, because she needed to keep her hair long while shooting Treme (2010).
Putting North Korean terrorists in the plot was widely viewed as prescient when real-world tensions between North Korea and the U.S. emerged in 2013. In an interview, director Antoine Fuqua said he did not want the film's villains to be from the Middle East, because he felt other films had covered that, to the point of saturation. North Korea was interesting to him, because it was completely closed off to the outside world, and no one really knew what it wanted or was capable of doing.
One trailer, used in television ads, included Emergency Alert System tones. They are used to alert television viewers about real-life emergencies; using them outside of emergency broadcasts or tests, violates federal law. In 2014, the FCC fined ESPN, Viacom, and NBC Universal 1.93 million dollars for broadcasting Emergency Alert System tones in non-emergency broadcasts.
Morgan Freeman was filming the crisis room scenes in Louisiana at the height of his Internet death hoax. He began each day of filming by serenading the extras with old jazz songs, and endeared himself to the unsuspecting crew with pranks.
While filming the White House tourist scenes in Louisiana, the weather was so hot that the Humane Society representative insisted that the German Shepherds playing K-9 watchdogs stay in an air-conditioned van between shoots.
Gerard Butler was once in consideration to star as CIA operative Mitch Rapp in a proposed film adaptation of Vince Flynn's novels. One's plot is very similar to this film; terrorists seize control of the White House, and Rapp must get to the President in his bunker before the terrorists do.
This is the fourth film in which Morgan Freeman and Ashley Judd have appeared in together, but this is the first time that their characters do not share any screen time together. The other films they worked together in were: Kiss the Girls (1997), High Crimes (2002), Dolphin Tale (2011), and Dolphin Tale 2 (2014).
The intruding aircraft is a modified Lockheed AC-130, itself a modified C-130 Hercules. In the movie, the plane has two GE M134 miniguns on each side. In real life, the aircraft only has air-to-ground armament on the left side to provide close air support to ground troops, among other high-risk tasks.
At different points in the Pentagon crisis room the Sergeant Major of the Army, the Chief Master Sergeant of the Air Force, the Master Chief Petty Officer of the Navy and the Sergeant Major of the Marine Corps can be seen. Each of those people are the highest ranking non-commissioned officers of their respective branches of the military, and are the ones in charge of overseeing the activities and deployment of the enlisted ranks. During a crisis like this, they, as well as the Joint Chief's of Staff, who are all four star Generals or Rear Admirals, and the highest ranking officers of each branch of the military, are brought in not only for their protection, but also to help with strategics.
When Banning gives Conner his badge, you can see that it is somewhat different from the badges the other Secret Service Agents carry. That is because Banning has been working for the Treasury Department, so he is carrying the badge of a Treasury Agent.
Aaron Eckhart and Gerard Butler have played characters who have deformities on half of their face. Eckhart played Harvey Dent a.k.a. Two-Face in The Dark Knight (2008), and Butler played the title role in The Phantom of the Opera (2004).
After the attack on the White House, and kidnapping of the President and Vice President, Speaker Allan Trumbull (Morgan Freeman) becomes Acting President of the United States. Freeman previously played the President of United States in Deep Impact (1998).
Whether it's coincidence or homage, Olympus Has Fallen contains a few allusions to the movie Die Hard (1988): The traitor who leads the North Koreans to the White House is ex-Secret Service Agent Davey Forbes. Die Hard villain Hans Gruber mentions to Mr. Takagi that he read an article about his company's wealth on Forbes. In Olympus, the scene where Forbes finds Banning, and casually smokes a cigarette before trying to kill him, is similar to the Die Hard scene where McClane finds Hans in a storage area, and has a cigarette with him, before Hans tries to kill him. Also Banning plays a cat-and-mouse game with Kang in Olympus via radio, just like McClane plays a cat-and-mouse game with Hans in Die Hard via walkie talkie.