Towards the beginning of the film when Neeson's character is walking through Grand Central Terminal, there is a poster for Paddington 2, which shared its US release date with The Commuter on January 12th.
Patrick Wilson plays a cop named Alex Murphy. This also happens to be the titular character's name in another cop movie; RoboCop (1987), although it is unclear if the reference is intentional or coincidental.
The trivia items below may give away important plot points.
The film's plot bears similarities with Neeson's previous film Non-Stop (2014). Both films feature Neeson's character traveling; both characters are looking for a passenger who is hiding something that puts others in danger; they're both suspected by authorities to be the criminals themselves; they both save the day at the end of the films.
A major plot point is the search for a character named "Prynne," which, as MacCauley discovers, is derived from the Hester Prynne character in The Scarlet Letter (1995), which the character is reading. Captain Hawthorne's name is probably a reference to the man who wrote original novel - Nathaniel Hawthorne.