I was wondering why some dvd's have trailers that are in different aspect ratios than the original movie. I do not mean from widescreen to pan and scan but rather from 2:35 to 1:85.
Many times, 2.35:1 movies are cropped for 1.85:1 trailers. Sometimes, 1.85:1 trailers are "windowboxed" on 2.35:1 (MIB II is one).
A lot of times, scope films are simply panned & scanned onto a flat trailer, which is later cropped on the top and bottom. One of these trailers is the old The Elephant Man trailer and the one for Deliverance.