Pick up any car (did it in a porsche because all other forzathons this week are with porsche)
and then drive / teleport to airport.
Then drive behind a other driver and press x when it is displayed to start a head to head race.
Advantage at airport is: you can use extreme shortcuts and AI always drives the marked way
Do this 5 times and receive 3 Wheelspins, 35k XP and your "Challenge Achievement"
Example - blue line = track - green = shortcut