Contributed by: politeintruder
From her autobiography "Neon Angel", Cherie Currie (The Runaways) was meant to be in this Film, playing the Mom I think and having acted in the Film "Foxes" years before, until they realized her drug habit was out of control and would affect production. Joe Dante had to let her go.
The homemade spaceship was christened "Thunder Road" which, as it states in the movie, is the title of a Bruce Springsteen song (from the album "Born To Run").
These are some of the major scenes that were filmed but removed from the final cut of Explorers. These are taken from the novelisation. We know that they were filmed as there are images for them in some merchandising material, and because Dante himself said the rough cut was over three hours long:
After Ben has been floating outside Lori's window, she hears him and calls out; she then invites him (and Wolfgang - who she doesn't know is also there) to a party she's throwing. This leads to...
A later scene at the party. All the kids are talking about the UFO scare at the drive-in. Steve Jackson is there boasting about his experience. Wolfgang tries to submarine Ben's affection for Lori by saying that he can read lips and that he can tell she likes Steve Jackson (this is in response to Ben wanting to tell her about the flight). Ben decides to talk to her. Wolfgang advises Darren the logical way to pick up girls, Darren starts out following Wolfgangs advice, then dumps it and gets slapped. Seeing the right moment, Ben takes Lori aside to talk to her. When alone, he gives her a ring with a martian rock in it, and then he tries to kiss her. She says she likes him but not that way.
The boys walk home and argue. Ben is upset because of Lori, and because the guys don't want to fly again.
*There is a photo of both the kiss and the argument in the storybook. There is also a photo of the kiss and Ben giving Lori the ring with a martian rock in the Starlog Explorer's Movie Magazine*
In a later scene when the boys are going up for the final flight, they are surprised by Wolfgangs brother who is playing in the Thunder Road wearing a mask. He won't leave, so Darren has to threaten to beat him up. *Photo of Ludwig and Darren at the Thunder Road in the storybook*
A final omitted scene has the boys (after the last flight), now changed and more mature, being threatened by Steve Jackson, who takes a gift that was given to Darren (not the "Stuff that dreams are made of" gift - which has been broken in transit) and squeezes it. It releases a green gas that causes his clothes to shrink and fall off. He has to run out of school naked with everyone laughing at him (this scene shows that the aliens were having a joke at their expense, by giving them a gift that would make Wolfgangs dream - mentioned earlier in the film - come true). *Photo of Ben, Lori and the guys all smirking together at school (after Steve has run away) in the storybook. There is also the same shot, a shot of Lori leaning on Ben's shoulder and saying something to him, and one of Ben standing behind a metal bar with his arm around Lori saying something to her, all from the same scene in the Starlog Explorer's Movie Magazine*
There are a lot more little bits involving family and stuff throughout the book: The guy at the drive-in who mocks Starkiller's effects is Ben's brother (who appears much more in the original story). There is more of Darren and his less than perfect home life scattered throughout the story. The opening dream sequence is longer - with Ben practicing flying. The final dream sequence is longer (beginning in Ben's house).
As a footnote, the original trailer for the film has the boys walking together in a tunnel at school (you also glimpse this in Darren's dream-machine sequence). They're never actually seen doing this in the film, and I think it was meant to be later footage of them at school after the final flight.