We've had a lot of interest in Thule Hullavators.
To use one, you need a Thule rack system on your car (square bars or Wing bars)
If you don't have a rack system, I have one that will fit a vehicle with raised roof rails that run lengthwise on your vehicle roof.
Here's some info from our own Nate Long on how to source one MUCH more inexpensively!
The Ford part number for the Hullavator is VKB3Z7855100Z. There is Ford dealers that sell that part cheaper than getting the Thule 898 through Thule and other vendors.