This thread is established for the discussion of Virgin Galactic
http://www.bbc.com/news/science-environment-35002459
i don't think this is new, but i guess its now formal that they are going to use 747 for a launch platform.
My critique here is that in that class the 777 is a better choice, given that it has a slightly higher flight ceiling and is less cistly to get to that altitude and back. If one is looking for altitude why not find an old concorde, if they still exist