According to Lou Diamond Phillips in the VH1 documentary "Behind The Music: The Day The Music Died" (1990), Ritchie Valens' sister was on the set the day they filmed the "coin toss" scene where Ritchie wins (or rather, loses) the chance to fly on the plane with Buddy Holly and The Big Bopper. As the scenes were being shot, Ritchie's sister began to weep uncontrollably and when Phillips tried to console her, she hugged him and sobbed, "Why Ritchie? Why did you get on the plane?"
Ritchie Valens' family were so attached to Lou Diamond Phillips that when he was shooting the scene where Valens gets on the airplane that led him to his death, the family begged Phillips not to get on, fearing that he would die.
The 1957 plane crash at Valens's Jr. High School which was referenced in this movie, occurred over the San Fernando Valley. A DC-7 and an F-89 jet crashed into each other over the San Fernando Valley. The two planes broke-up in the air, and the DC-7 plummeted from the sky onto the playground of Pacoima Junior High School. Valens did not attend school that day because he was at his grandfather's funeral. At the time of the crash, students were at recess on the playground. The crew of the DC-7 were killed, as were several students on the playground. 74 more students were injured. It was this plane crash that caused Valens to have a fear of flying.
At the first family party, the old lady sitting by Ritchie and the man is Ritchie Valens' mother, Connie Valenzuela. She died on October 18, 1987 at the age of 72, only three months after the film's release.
The band playing the traditional folk version of "La Bamba" at the club in Tijuana is, in reality, the band Los Lobos, who performed all of the Ritchie Valens music for the film. The guitar player next to the bass player is David Hidalgo, who provided the singing voice of for Lou Diamond Phillips.
Before Lou Diamond Phillips auditioned for the role, his agent mistakenly told him that the film was about Frankie Valli. Phillips did not think he was right for the part but went to the audition anyway.
Toward the end of the movie, when Ritchie and Donna are cruising down the road, Ritchie asks Donna if she'll wait to marry him. He says "Just till I'm 25 and I have a big, glass cabinet to keep all my gold records in". Lou Diamond Phillips actually was 25 when he played the role of Ritchie Valens.
In this movie, Jackie Wilson is played by Howard Huntsberry. Two years later, two versions of the song "Higher and Higher" would be used in the movie Ghostbusters II (1989); the first is the Jackie Wilson version in the toaster scene, and the other is a cover by Howard Huntsberry used in the Statue of Liberty scene.