Final Fantasy: The Spirits Within Easter Egg - Miscellaneous Vehicles

Load DISC TWO of the Special Edition DVD, access the DVD menu and choose 'Highlights Menu', then 'Vehicle Comparison'.
On this screen, highlight the exit arrow button (bottom left) and move right twice.
This will highlight an star emblem/badge that takes you to a special montage of miscellaneous vehicles that were included in the movie, either visible in the background, or used as a secondary prop (or possibly even left out of the final cut.)