You'd probably get this eventually anyway, but if you want to knock it out early the Jezioro Lukie stage in Poland has a big enough jump a little over 30 seconds into the stage. Take a fast car like the VW Polo GTI R5. It's actually the second of a pair of "big jumps" mentioned by your co-pilot. Hit the jump and restart and repeat until you get them all. If you don't come across this stage while going for the other achievements, go to Free Play and create a Custom Championship and set this stage as the 1 stage for the event. You could knock out another achievement while you're at it if you continue on and finish the event instead of just restarting after each jump. Up to you.
The Paskuri stage in Finland also has several huge jumps in the first part of the stage if you happen to have the Season 3 DLC.