Factual error: Tommy is wearing a Hulkamania shirt while the band is being assembled together. The band was formed in 1981. Hulkamania didn't start until 1984.
Factual error: The film is set in 1987 but most of the street lights seen throughout the movie are LED street lights and some high pressure sodium Philips lanterns (produced from the early 1990s to early 2000s), neither of which were around back then. Similarly many of the shots of the M1 motorway show modern cars and smart motorway/variable speed limits, which never existed at the time.
Factual error: When we see Elton John's father Stanley in RAF uniform at the beginning of the film he is wearing other ranks' uniform. Stanley was commissioned in 1944, three years before Elton was born, and served as a commissioned officer until his retirement as a squadron leader in 1963. He should be wearing officer's uniform.