After Kevin Costner's character leaves to save Enola from the smokers, Helen and her crew decide to go help. The camera pans out to show the blimp, but located conveniently behind the blimp is a large part of the Californian coast.
the movie was filmed of the kohala coast in hawaii, the props are on display near there. the "island" at the end was wapio valley on the northeastern side of the coast. the reason the movie was so costly was that costner stayed in a $7000/night prince suite hotel