What is he going to film first? He's 71 and he has a lot on his plate!
Well on IMDB it has the date 2011 for the Alien Prequel. I know IMDB can be wrong, but there are a few things that makes me believe this to be so. First, his next movie, THE KIND ONE, sounds just like a low budget period drama, so I don't believe that would take too long to do. Second, Fox will probably want to get the project going as soon as possible, with all the franchise activity happening next year. Lastly, I think it would be easier for Scott to make the Alien Prequel because Fox are already behind him on that one, while The Forever War and Brave New World are more of a risk, financially.
I would think those movies would come later. The Alien Prequel will probably be a financial success, so that would give him some argument for getting the funding to do another science fiction film with a budget.
Scott must be on steroids...
I heard Brave New World was just fan speculation of what his next "sci fi" would be, and that it was actually going to be Forever War.