New Earth car
From Tardis Wiki, the free Doctor Who reference
New Earth Cars were the general transport on New Earth. They were the hovering version of the 21st century cars.
Thousands of cars were trapped in The Motorway, under the city of New New York for 23 years. It would take months just to go one mile (although the whole motorway just went in circles). The Doctor saved the people by opening the roof of The Motorway, all cars flying upwards to repopulate the city. (DW: Gridlock)