IG Model Gracie Bon Says She's Serious About Bigger Plane Seat Petition

Gracie Bon's goal to get bigger seats in airplanes to accommodate her huge ass might've gotten a laugh on social media -- but she's not chuckling ... telling us she's dead serious.

We talked to the Instagram model about her recent viral "petition" about rejiggering the configuration of flights -- so that seating areas are larger, for people of size to fit comfortably -- and while she admits it was half-jokey ... there was some truth to what she was arguing for.

As she explains to us here ... this issue is actually quite pervasive, and it often gets turned into one big punchline at the expense of people who are truly struggling with it.

Yes, she's got a big butt ... something she says she can't help, and for which she shouldn't be punished either -- that's her argument anyway.

She also says people chiming in with mean/hurtful comments aren't helping either ... and she thinks companies should be more thoughtful about customers of shapes and sizes.

Gracie says she's actually used to buying two seats to deal with this problem -- and figured a first-class flight would solve it -- but to her dismay, it didn't ... and she now realizes that some major changes need to be instituted to address this very real problem. No, she's not kidding.