Kourt and her husband, Travis Barker, flew commercial on Alaskan Air for a trip from LAX to Spokane, Washington earlier this week.

Kim Kardashian and Travis Scott were among the celebs to make that list -- and, as we reported, Kylie Jenner's carbon footprint has also been a hot topic after she posted a shot of her and Travis with his and her private jets.

It's safe to say Travis and Kourtney are doing what they can to stay off the planet polluters list!