Factual error: In circling over Washington Dulles, a plane would fly over several airports that they could land at with perfect communication, including Richmond, Baltimore, Andrews AFB, etc. Also, there is no communication from the airport to the plane but the plane would be in range of no fewer than 15 transmitting stations that could have relayed messages.
Other mistake: In the slaughterhouse scene, after Harrigan has injured the Predator with his shotgun and Keyes reappears, the Predator throws its disc, and severs Keyes in half at the waist. We see his legs flop to the ground, and blood pour from above, but his upper half (torso, backpack and weaponry) mysteriously remain hovering out of sight. (01:21:50)
Other mistake: At the carnival, you can see an African-American man staring at the camera for a while. I am unsure if he is a crew-member watching over the scene, or if he is just an extra trying to get onscreen.
Factual error: Mel and Goldie board a ferry. A visible sign states 'Detroit-Racine Ferry'. Detroit is on the east side of the state of Michigan but Racine, Wisconsin is west of Michigan, across Lake Michigan. The only water route to get from Detroit to Racine would be to circumnavigate the entire state of Michigan.
Revealing mistake: Doug has the hologram when inside the alien nuclear reactor, and a bunch of bad guys encircle the holographic image and fire at it at point blank with automatic weapons, and not one bad guy gets hit. If they encircled the 3D image, at least a few bad guys would have been hit by their own men. (01:37:00)
Continuity mistake: At the end of Rocky IV, Rocky's son Robert is around 6 or 7 years old. After Rocky comes back from Russia in Rocky V, his son is around 12. While there was a 5 year interval between Rocky IV and V, no time had elapsed from the two in movie time. So, therefore, his son should still be the same age given that Rocky has just recently fought Drago, "The Russian" considering his bruises, and they all returned home right after the fight.
Continuity mistake: At the start of the movie when the gun store is being robbed, one of them fires a portable rocket launcher at the police car, causing it to roll over and spin. As it comes to a stop just outside the store, it's visible that the driver's side window has been blown out, and the vehicle interior is visible, however when the same guy prepares to fire the bazooka to finish it off, the window has returned and is completely intact.
Continuity mistake: When Ford and Jazz are at the Colleen Sutton party, Jazz is asked to keep an eye on Colleen. Collen spots her and put a CD down her dress with the black end facing downwards. When Ford is taking the CD up from her dress the black end is now facing upwards. (00:43:25 - 00:45:00)
Factual error: Though extremely modest on today's standards, the dress worn by Clara to the hoedown shows far too much cleavage for the time. No schoolteacher would ever wear a dress like that in the 1880s.
Continuity mistake: In the scene when Billy is shooting Doc's handcuffs, Billy's revolver changes several times, shot by shot. Watch for the front sight to appear and disappear between the POV Doc shot and the medium distance shot, and for the entire finish of the gun to change at least twice.
Factual error: They hold a huge dance in the hangar at night, and Dennis leaves to walk to the Memphis Belle through the hangar doors, which are wide open. The whole flight line, tarmac and hangar are bathed with light - on a US Air Force base in East Anglia during the blackout. Blackout restrictions were rigidly enforced and were not eased until September 1944. The last mission of the Memphis Belle was in May 1943.
Continuity mistake: In one scene, Chucky and a girl are driving down a road when they get pulled over by a cop. The cop is surprised to see a "Good Guys" doll, and is shocked to see that its nose is bleeding. They do a close up of Chucky's nose, and blood is running from it. When they cut to the cops point of view, where Chucky and the girl are both in frame, the blood is gone. It doesn't reappear for the rest of that scene, even though no one wiped it away. (00:54:55)
Other mistake: When Seagal is in the factory in Jamaica, a "Jamaican" bad guy jumps up from behind a barrel, you can see that he is in fact white - you can see the make-up line on his neck, and his wig is crooked.
Continuity mistake: Near the end of the film, when the SEALs are in the inflatable boats heading towards the coast of Beirut, there is a shot from behind showing all the SEALs wearing black diving suits. But when the shot changes to a close up of their faces, you can see they are wearing camouflage fatigues, not diving suits.