Amazon UK Customer Review: M. Hevingham "Mark Hevingham" said:
Like the VHS and laser disc releases this movie is ruined on DVD by a ten minute cut and pretty awful cropping of the image.
When it was shown on TV (Sky movies in around 1990) it was shown 4:3 but with the full running time which is shorter by around 10 minutes in the home video release. ...
The film was shot in 2.35:1 and is cropped here to 4:3, momentarily appearing in 16:9 within the 4:3 frame to accommodate the movie's title.
I watched beyond some of the widescreen opening (wide only for the title) of a fullscreen Slipstream at YouTube. I also noted that the end credits list Panavision and Panaflex equipment. Could it be that Slipstream was a cinemascreen production, as the Amazon reviewer states? In those early minutes of the pan & scan video, there is a shot that starts at the right and quickly pans left to following the action. Putting together those two extremes showed what the original shot might've looked like:
From my added frame outlines, cinemascreen (in cyan) would've looked awesome. Unfortunately, it seems widescreen (in magenta) contains the entire shot, well-framed for that format.
As jerryshadoe mentioned above, there are "HDTV" and "Cinemascope" vids at YouTube. And, yes, they are just poor quality, crop-and-stretch vids (karma will get back to YouTube poster "Gunga Din" & "gunga din" for that bit of trickery). ;)
However, there is a "making of" video there, too. These are interesting because they show original movie clips (interspersed among the interviews) in the movies' released format:
The Making of Slipstream (1989) (by the director of Tron)
Grabbing the same-frame shots from the fullscreen movie ..
.. and from that widescreen portion of the "making of" documentary, and superimposing them, shows further evidence of Slipstream being a widescreen (only) production:
Also came across a medley of Elmer Bernstein music from the film (must be from a soundtracks compilation):
Elmer Bernstein - music from Slipstream (1989)
and a few minutes video capture from the JP laserdisc:
Slipstream widescreen test clip
YouTube coming through big time! Hope this helps.