How do the puzzle pieces suddenly fit together so perfectly to suggest they're definitely going with that oft-rumored alien plotline? This story takes place after 1947. Are people just getting the idea that the big "unlocking" moment for Indy will be discovering that every mystical thing has been alien and that the Roswell ship will be the key? What if it takes the route that the story about little green men actually was just a story and that the actual truth is more along the lines of something fantastical/mythical like we saw in the other three movies?
Which draft of the script did the alien idea show up in anyway?
Oh, and I'm throwing in my opinion that space aliens in Indiana Jones would be just a tad bit more out of place than midichlorians in Star Wars.