Factual error: After the plane is submerged, Jack Lemmon says, "... this plane is pressurized!" Jet aircraft are pressurized by bleeding air from the compressor sections of the engines into the cabin; in other words, the plane is only pressurized while the engines are running. Also, aircraft are only pressurized to a few psi above the outside air pressure at altitude, and never to more than the air pressure at sea level. The water pressure would be a great deal higher than the air pressure in the cabin, and since aircraft are not water tight, the water would quickly fill the aircraft. (If the aircraft was in 50 feet of water, the water pressure would be 21.7 psi, versus a maximum cabin pressure of 14.7 psi.)
Continuity mistake: Jack Lemmon is picked out of the ocean by two men in a rubber boat. Both have dark hair and moustaches, one is balding. When they arrive back at the ship, both men have blond hair, are clean shaven, and are obviously younger. (01:24:10 - 01:24:55)
Continuity mistake: In order to show the take-off of Stevens Corporation's 747, a scene from "Airport '75" is used - the plane's tail fin reads "CA" (for "Columbia Airlines") instead of showing the Stevens Corporate Logo.
Factual error: In the many shots of the plane underwater, both from outside and looking out from within, the "sea" resembles the bottom of a swimming pool more than the bottom of a shallow area of ocean, as not a single fish or any other aquatic life (which would be abundant in areas around The Bahamas) is ever seen.
Factual error: In the opening credits, the plane is showing landing over the Capitol Building on the way to Dulles. Dulles is no where near the Capitol Building.
Continuity mistake: Eve tells the Captain about her job in Geneva. His right hand appears/disappears/reappears randomly on her cheek.
Factual error: The function of the US Navy in this movie in being called to raise an intact aircraft is plausible. Their actual role is usually to do with raising submarines. That being said, what isn't plausible is for a 747 to be heavy enough to cause equipment such as strapping to snap and fail, when a submarine is so many magnitudes heavier. A fully laden 747 can be over 400 tonnes, a moderate Los Angeles class submarine is over 6000 tonnes.
Factual error: Whilst the use of air-filled balloons is entirely credible when raising something like a 747, the air balloons would not lift the aircraft out of the water. The balloons would go as high as the ocean surface and no higher, meaning the access doors to escape the aircraft would still be submerged.
Plot hole: The crash as presented in the movie is beyond preposterous. The tail fin striking the ocean surface would have torn it off. Even if we pretend the tail fin would be strong enough, the aircraft would catapult onto its nose and break up, meaning no survivors.
Continuity mistake: When the Captain is rescued by the Navy Zodiac, there are two Navy guys, one with a T-shirt on, the other bare-chested. When they get back to their ship, both Navy guys now have T-shirts on.
Other mistake: The watch on Robert Foxworth's arm is a Hamilton 2-dial chronograph... but it is upside down. When Palm Beach is radioing the plane to find out its location, Foxworth looks at his watch. The Hamilton name and insignia are on the bottom when they should be on the top. (00:39:55)
Continuity mistake: At the airport newsstand, when the pilot and the bad guy swap suitcases, the bad guy closes his magazine. A shot later, it's open and he closes it again.
Revealing mistake: While the plane is almost upside down, papers and stuff fall inside, but one can notice that it's the actors throwing the papers, not gravity making them fall.
Continuity mistake: When the little girl holds the drawing, her right hand appears/disappears on the upper part of the paper randomly. (00:16:12)
Continuity mistake: When Eve and the Captain hug, her right arm is either tight around his neck or lowered next to his shoulder. (00:10:19)
Continuity mistake: When Philip arrives at the mansion, a photographer on the left walks around and stands on the right. A shot later she is back on the left side. (00:01:45)
Continuity mistake: When Karen attempts to open the submerged plane's outer door, the fastener on the back of her shirt is done up incorrectly, then it is suddenly buttoned the right way.
