Visible crew/equipment: Lighting screens are reflected in Hepburn's glasses while she's in the car heading to the set.

Continuity: When the Hercules first flies, the boats on the water below suddenly disappear.

Continuity: When Hughes takes off to fly (and crash), a huge zebra crossing magically appears on the concrete.

Deliberate "mistake": During the flight Hughes takes with Katherine Hepburn, they talk to each other in normal, conversational voices. A twin-piston-engined aircraft of that vintage (or any vintage for that matter) is LOUD. We should be able to hear roaring engines, and the two should have to shout at each other to be heard.

Continuity: After Ava Gardner shaves Howard, she instructs him to wash off his face. He looks at the sink and all of the water drains out. Then there is a shot over the sink as he is about to rinse off his face with a lot of water in the sink. It should still be empty.

Continuity: After the plane crash, when Hughes is lying on the floor we see his left trouser is undamaged, but a second later it's in rags and the part going from the knee to the foot is missing.

Continuity: At the end of the scene in the Coconut Grove, with Howard Hughes and his young girlfriend, Faith, eating a sundae, Howard's arm switches between shots from being over Faith's shoulder, to in front of him. He is seen in one shot removing his arm from her shoulder and wiping his hand because he shook Juan Trippe's hand. In the next shot his arm is over Faith's shoulder again, and in the shot after that, he is wiping his hand again.

Continuity: In the scene when Howard Hughes and his young girlfriend Faith Domergue are in the Coconut Grove meeting with Juan Trippe, Faith is seen with a sundae in front of her. In one shot, she's eating the sundae, and in the very next shot her hands are suddenly in her lap.

Revealing: When Leonardo DiCaprio is wiping blood off his hands in the bathroom scene, you can tell the blood doesn't really come from cuts. It's just fake blood they put on his hands for that scene.