Development Hell: The project's genesis was in 1979, with Ridley Scott joining as a producer in 1980 with Callie Khouri intending to direct it. At several points, a few big-name actresses were attached to or considered for the titular roles.
What Could Have Been: The alternate ending (had it been used) would have explicitly made clear that both women died - the car is seen flipping end-over-end as it goes down into the canyon, and Slocumb stops at the edge of the cliff and looks on mournfully while a helicopter swoops down to the canyon floor, all set to B.B. King's "Better Not Look Down". The film would end with a shot of the vehicle continuing to drive off into the distance, symbolizing that although both women had died, they would continue their journey in the afterlife.
George Clooney auditioned for the JD part five times. William Baldwin was originally cast, then dropped out to do another movie. Brad Pitt—who'd auditioned for the part Baldwin got—ended up being cast.
In 1980, Ridley Scott had Natalie Wood in mind as Thelma and Tuesday Weld as Louise.
Meryl Streep and Goldie Hawn also considered the script.
Callie Khouri wanted Holly Hunter and Frances McDormand as Thelma and Louise