Inspired by the story of Merhan Nasseri, an Iranian refugee. Dreamworks reportedly paid him $250,000 for the use of his biography. In 1988, he landed at Charles de Gaulle Airport near Paris after being denied entry into England because his passport and United Nations refugee certificate had been stolen. French authorities would not let him leave the airport. He remained in Terminal One, a stateless person with nowhere else to go. He has since been granted permission to either enter France or return to his own country. He instead chooses to continue to live in the terminal and tell his story to those who will listen. Reportedly, his mental health has deteriorated over the years. When given the opportunity to live in France, he refused because the documents did not name him as "Sir, Alfred", and he claims to have forgotten his native Persian language. Reportedly, he left the terminal in August 2006 to be hospitalized for an unspecified illness.
Steven Spielberg cut a line from the film where Navorski gets help using a phone card and says, "Home phone, home phone!" Spielberg cut this because he didn't want comparisons to E.T. the Extra-Terrestrial (1982) and the famous lines "Phone home."
The terminal set was a near-full-size replica built in a former hangar, with three working sets of escalators, and populated by many familiar stores (e.g. Burger King, Mrs. Fields, W.H. Smith). Some of these brands were recruited by Dreamworks, while others approached the studio when word of the production got out. Many of the stores and restaurants were built by the construction crews that build actual mall and airport stores for the respective companies, and some had fully-functioning equipment, such as ovens and cash registers. However, the inclusion of a brand on the set was not a guarantee of inclusion in the film; Dreamworks retained full control over editing, and some brands appear only briefly or not at all.
Although Viktor comes from the fictional country of Krakozhia, the language he speaks in the movie is Bulgarian. The written material shown (the Fodor's guide and the magazine page with the jazz greats) is in bad Russian. The label on the Planters peanuts can is neither in Bulgarian nor in Russian. Viktor's driving license is issued in Homel, Republic of Belarus, and has a woman's name on it (written in Cyrillic) - Gulnara Gulina. It was a real license provided by a real Gulnara Gulina, a woman from Belarus who was working in American movie industry, although the license, issued in 1995, was already invalid at the time of filming. The filmmakers just added Viktor Navorski's name in English and his photo.
The main character of this movie was originally scripted to arrive from Slovenia but this was changed after the advice from the former consul of Republic of Slovenia in the United States Mark Rijavec. Since Slovenia is by some considered to be Switzerland of the Eastern Europe it would not look credible would a civil war be started in one of the new members of the European Union.
It is mentioned that Officer Torres (Zoë Saldana) attends Star Trek conventions. When Torres accepts his marriage proposal greets Cruz (Diego Luna) with the "Vulcan Salute" from Star Trek. Saldana later went on to play the role of Uhura in the Star Trek films, in which she dates Spock, a Vulcan.
In the scene where Viktor is avoiding the security camera near the exit, the camera is of the Espree line manufactured by Pelco in Clovis, CA. The motor noises had to be added to the film, because the Espree PTZ (Pan, Tilt, Zoom) features operate virtually silently.
In the French version of the movie, Dolores Torres says to Viktor that she goes to Star Trek conventions dressed as Uhura. In France, the Star Trek series is not as well known as in America and it was thought that the character of Yeoman Rand was less well known than the principal crew of the starship. 5 years later Zoe Saldana, who plays Torres, would appear as Uhura in Star Trek (2009) and its sequels.
After the Inspectors from Immigration, Customs, and Agriculture combined to become Customs and Border Protection (CBP) it took time before the new CBP Officer received the uniform depicted in The Terminal. At the time of filming many CBP Officers had not yet been issued the new uniform.
The film was shot with two endings. The original version of the film, previewed in Orange, California on 26 May 2004, had the other ending, in which Catherine Zeta-Jones's character Amelia goes into Manhattan with Viktor. The changes to the film caused the start date of Steven Spielberg's next film Munich (2005) to be pushed back a number of weeks, which meant that Ben Kingsley could no longer appear in it, due to his commitment to appear in Roman Polanski's Oliver Twist (2005).
The charactors played by actors Diego Luna and Zoe Saldana, end up getting married towards the end of the movie. The same two actors voice charactors in the animated movie The Book of Life (2014) who are love interests also, and are married by the end.