Doc and Daniel Clayton fly in a homemade glider.
A glider is a non-powered vehicle that achieves flight through gliding on wind currents.
In 1850, Verne Brown and Martha O'Brien were trapped by a bear in Wyoming, on the land that would become the Yellowstone National Park. Doc recognized Old Faithful, and told them to sit on the geyser, on top of a buffalo hide, to insulate them from the hot water and steam.
Doc built a homemade glider from the wagon cover that disguised the DeLorean time machine. Doc and Daniel Clayton flew to the geyser and rescued Martha and Verne. Martha fell in love with her savior, and soon after, she became married to Daniel.