It's pretty likely that most, if not all, of the in-flight/space shots will be done with CGI. But the rumors of a full size MF likely means that they are really going out of their way to surround the actors with tangible sets and scenery, which is great.

90% of the character based green & blue screen used in the prequels is distractingly noticeable. It will be nice having actors interacting with real sets. Not only for aesthetic reasons, but also for the sake of the actors and their performances.