Blooper

When Ben pulls Alex from the frozen lake, the knit cap she's been wearing is gone; it has come off in the water. Later when they set out again she is wearing the hat.

When the pilot suffers a stroke, Alex [Kate Winslet] is behind the pilot on the left side of the plane and Ben [Idris Elba] is on the right side behind the co-pilot seat. They both face the rear of the plane and brace for impact as the plane crashes. When they wake up after the crash they have switched sides: Ben is on the left side and Alex is on the right.

When Ben pulls Alex out of the lake, her blue splint is around her ankle. When he carries her to the cabin, it is back up to her knee.

The camera that Alex uses is a Leica M4-P made from 1980 to 1986 and is a 35mm film camera. At the beginning of the movie the camera has image review, a feature not found on film cameras and it also has auto focus capabilities something not found on a Leica M4-P. By the end of the movie the camera is back to a normal Leica M4-P with a roll of film and a developing scene.

Mountain lions are stalk-and-ambush predators requiring heavy vegetation in which to hide, and so would not wander around above the treeline.

During the film Alex shoots with a Leica M4-P camera, which is a 35 mm camera. At the end of the movie when she is developing the pictures in the darkroom, she is looking at medium format negatives, which usually are 60 x 60 mm.

When a plane loses its tail section it will not continue flying level and straight, as the plane in the film does before crashing.

For the aircraft model depicted, a Piper Navajo, the engine noise inside in the cabin during flight is way too silent for cruise situation. There would be either no possibility that, without headphones, they could listen to each other talking in normal voice or that the pilot, who happens to be wearing headphones, could have overheard the passenger's conversation about London.

There should have been steam rising from the urine when she used the basin to relieve herself.

Questioning or demanding an unnecessary flight-plan is a rarity with passengers & only gained attention post- 9-1-1 when people became convinced that'd make any difference in safety, which it doesn't. This flight was in radio- & radar-contact all of the time & a SAR-launch would've occurred soon after loss of contact, & certainly no later than 30 minutes overdue the ETA.

Ben could have called a few people, air-traffic control, fellow pilots from the airstrip, relatives etc with a bit of research to find out the name of Walter's dog instead of just calling him Dog.

When Ben is trying to convince Alex to come with him in the cabin, the head of a crew member can be seen briefly in the doorway behind them.

Around 47 minutes into the movie, Ben (Idris) and Alex (Kate) are arguing whether they should climb down the mountain around the waterfalls, Ben says they'll die if they go down the path. When Alex remarks "last time I thought", you can see a crewman in black walking in the background.

Walter mentioned being a fighter pilot for the 48th at RAF Mildenhall. Although the fighter planes are assigned to the 48th Fighter Wing, that is at RAF Lakenheath not Mildenhall.

Alex and Ben never put their hoods up or fully tie their scarves around themselves (instead letting them hang down fashionably) even though they're outdoors in winter all day.

Take a look at the dog. It has to be very slim and not so active after 3 weeks starving. You are freezing- warm animal near you.