The crash was inspired by a real life disaster, the crash of Alaska Airlines flight 261. Some elements in the film are lifted nearly verbatim from the accident, such as the jammed stabilizer and requesting a "block (of) altitude" from traffic control. The pilots also, like in the film, rolled the airplane to an inverted position to try and halt the dive. Unlike the film, however, this did not assist them in recovering the aircraft. In the real life accident, the root cause was found to be inadequate maintenance that made the jackscrew that controls the stabilizer wear down and jam. Eventually the treads of the jackscrew were ripped out, the stabilizer flipped up and the plane became uncontrollable.
The script was first optioned by Denzel Washington's then agent Ed Limato who'd been kicking it around Hollywood for several months until Denzel showed interest. However, in order to get the film made with the studio's modest take-it-or-leave-it $28m budget, Washington and director Robert Zemeckis accepted a reported tenth of their usual salaries.
According to producers Steve Starkey and Jack Rapke (during a Q&A session with the Producers' Guild on October 18th, 2012), the primary airplane in the film is a pastiche of several existing commercial airliners so as to not ID a particular plane or airline in the film. Also, no promotional consideration was paid by any of the alcohol brands featured in the movie; they decided to feature beer, wine and hard liquor brands for one shot only so as not to "endorse" any of them.
According to Denzel Washington, American company Delta Airlines granted the production team access to their official flight simulator in order to learn some of the most common maneuvers pilots have to master in order to fly a commercial plane.
The flight number, 227, used in the movie is a common superstition to those flights that have crashed where the flight number digits add up to 11. A number of spectacular airline crashes also had this feature such as AA 191, the DC-10 that lost an engine in Chicago and crashed in 1979 as well as PSA 182 that nosed dived into San Diego in 1978 (where the pilots and flight attendants had been drinking and frolicking the night before as overheard by passengers who got off the same plane in Los Angeles).
John Gatins was inspired by a pilot who happened to be a fellow passenger on a flight. The pilot went on about his family life and issues which gave Gatins pause and made him realize that whenever he is on a plane he has to entrust himself to a stranger who is only human after all.
In the elevator with the small child, as Whip wipes his nose, a muzak version of The Beatles' "With a little help from my friends," can be heard. The verse begins, "I get high with a little help from my friends," right after Whip's friend gets him high.
When Nicole throws her purse on the coffee table, knocking over a box of drug paraphernalia, the song "Under the Bridge" by Red Hot Chili Peppers is playing. 'Under the Bridge' is about Red Hot Chili Peppers lead singer Anthony Kiedis' experiences shooting heroin under a bridge in downtown Los Angeles.
When Nicole (Kelly Reilly) is asking Kip for some money on the set of a porn film, she is told that she should play Desdemona. Kelly Reilly once played Desdemona in a famous Donmar Warehouse production in London with Chiwetel Ejiofor as Othello and Ewan McGregor as Iago.
In real-life Denzel Washington rarely drinks, and during an interview promoting the film he claimed he would never play a role genuinely drunk, as the results he's seen have been invariably embarrassing.
In the earlier movie High Road to China (1983), the character of Patrick O'Malley (Tom Selleck) drinks heavily and flies a plane whilst hungover, even flying it upside-down. These combined story elements are performed by Denzel Washington in this movie, as well.
Towards the end of the film when John Goodmans character appears for the second time, when he leaves the hotel room he says to the lawyer and union characters, "see you on the dark side of the moon". He previously played hound in Transformers: Dark of the Moon.
The trivia items below may give away important plot points.
At the end of the movie when Whip is at his trial, when asked if he thinks Catarina Marquez drank the vodka he says,"God help me.", which is the third step in the AA 12 Step program. The first, the admission that one is an alcoholic, is also voiced by Whip shortly after he speaks the first.
Viewers theorize that the man with cancer in the beginning of the film was actually God speaking to Whip and Nicole. He makes several references to believing in God and encourages Whip to befriend Nicole (without her, Whip's downward spiral wouldn't have happened). Before leaving he tells Nicole that she will be okay, which turns out to be true.