Board Thread:General Discussion/@comment-4436775-20130713014204/@comment-1824272-20130907163607

It's one of three things:

1. They managed to cut down a little data here, a little data there, to optimize the game, and with all of the little optimizations, they managed to cut out 1.4 GB of unnecessary clutter.

2. They cut out content (story/aircraft/etc.) that amounted to 1.4 GB, which may be included in the future as either patches or DLC.

3. They cut out content, which amounted to 1.4 GB, which will not be re-added.