Forza Horizon 3 - Personally, I Prefer the Air

Pull off 10 Ultimate Air Skulls in the RJ Anderson #37 Pro 2 Truck on Blizzard Mountain - 20

The RJ Anderson #37 Polaris RZR-Rockstar Energy Pro 2 Truck is free with the DLC. This is an easy achievement. If you need help, driving round the Snow Park, taking the jumps are speed will give you an Ultimate Air Skill each time.

RJ Anderson #37 Polaris RZR-Rockstar Energy Pro 2 Truck - 2016