It appears that Apple has begun quietly phasing out its trailer download options from the trailers.apple.com website, effectively eliminating 1080p trailer availability.
While trailers uploaded before May 22 can still be downloaded, Apple appears to be removing the option from movies with multiple trailers that have a trailer uploaded after that date. For example, Disney Pixar’s Monsters University has trailers that were uploaded on the following dates: 6/20/12, 3/08/13, 5/20/13, and 5/22/13. None of these trailers have download options.
Disney’s Planes, on the other hand, has trailers that were uploaded on the following dates: 3/15/13, 04/04/13, and 5/17/13. Each of these trailers can still be downloaded at all resolutions, including 1080p.
So, while older trailers can still be downloaded from the site, Apple appears to be removing downloads from older trailers as newer trailers are added, slowly phasing out the availability of trailer downloads altogether.