The production team purchased and then crashed a real 747 airplane into a hangar. The stunt was all practical effects, with no visual effects or CGI. Director Sir Christopher Nolan had originally planned to use miniatures and set-piece builds. However, while scouting for locations in Victorville, California, the team discovered a massive array of old planes, and it became apparent that it would actually be more efficient to buy a real plane of the real size and to perform the sequence for real on camera.
There was much secrecy surrounding the project before its release. Actor Robert Pattinson said that he was only allowed to read the script in a locked office at Warner Bros. studios. His co-star Sir Michael Caine wasn't even allowed to read the entire screenplay. He was given his scenes only to read before shooting. Prior to the movie's release, Caine told press that he had no idea what the film was about, despite being a very close friend and a frequent collaborator of director Sir Christopher Nolan.
In addition to performing stunts backwards, the main cast actually learned how to speak in reverse for their roles. Sir Kenneth Branagh not only learned how to speak backwards, but also had to do it with his character's Russian accent.
When the coronavirus pandemic hit the United States in spring 2020, the film's score was roughly eighty-percent finished. The only thing it really affected was an orchestral session that was scheduled for April. As a result, part of the soundtrack was completed by putting together individual recordings of the musicians in their homes.
Actor Sir Kenneth Branagh revealed that he read the screenplay for the film more times than anything he had ever worked on. He compared navigating through the script to doing the 'Times' crossword puzzle every single day.