The set for the plane was built slightly larger than a standard commercial airliner, to accommodate Neeson's 6'4" height for filming. According to Neeson, over 90% of the shoot occurred in this 'plane' over a two-week period.
Liam Neeson has frequently been cast as an American agent, or soldier, but this is a rare film where his Irish accent, which Neeson uses in most of his films, is acknowledged and explained.
Roughly two hundred extras were cast, and stayed throughout filming.
From the moment Bill Marks (Liam Neeson) starts his announcement to the passengers and crew about phone inspections to the moment he duct tapes Tom Bowen (Scoot McNairy)'s hands together, the scenes all play out in a single take.
The movie is exactly 100 minutes long (not counting the closing credits) and exactly five people die on the plane. This agrees with the terrorist's promise to kill one person every 20 minutes.