Trivia: Indiana Jones And The Saucer Men From Mars
In the mid-90's, George Lucas proposed an a fourth Indy film called "Indiana Jones and the Saucer Men From Mars." Jeb Stuart, screenwriter of Die Hard and The Fugitive, was hired to pen the script. An unconfirmed 1995 draft showed up online ten years later, and the story involved an alien artifact which continuously changes possession between Indy, Russian badguys, and aliens from another planet.
IndyFan.com described the story as "convoluted and unbelievable," and the script ends with an indulgent sappy sequence with Indy marrying the lady linguist who accompanied him throughout the adventure, with a ceremony witnessed by all the living characters from the films including Short Round and Henry Jones, Sr. If that doesn't sound bad enough, let me say that Indy also encounters crocodiles and pirates on this adventure. You can still find that draft by doing a quick google search.
Ford told EW "No way am I being in a Steve Spielberg movie like that." Steven Spielberg was also not happy with that idea, and admitted publicly that "There was a point where I thought George and I would never agree on the story." It took more than a decade to come up with a screenplay that Ford, Spielberg and Lucas were all willing to settle on.
On What has changed from Then to Now:
"It was the three of us, Steven, George and I, coming to agreement on the central notion of it all," Ford explained. "I think the original idea is still a large piece of it in the movie, but it's been developed and worked on in ways that made it a lot more palatable to Steven and I."
Lucas told the AP: "The MacGuffin of it slowed down a little bit from what my original enthusiastic version was. Again, that's the way it works with Steven and Harrison and I. We're not going to do anything anyone's uncomfortable with. We want to do something everybody likes, we in the group, the three of us. They wanted to go off on some other tangent. I said, 'I'm not going to do that. I'm going to stick with this no matter what, so we either do this or we don't. That's it.' Finally, we got something that we could all compromise on and all be happy with. It wasn't quite as wacky as I wanted it to be, but it still is subtle and nice and works really well and has the same idea behind it."