Playboy Model Sara Blake Cheek Says She Was Told to Cover Up on Flight

A Playboy model says she got dress-coded on a recent American Airlines flight ... and, she thinks her hair color and the size of her chest are major reasons why.

Sara Blake Cheek spoke to us about a recent experience flying with the company ... she says she made it through security, scanned her boarding pass and got all the way to the plane, when she claims a flight attendant told her to button her flannel and cover her sports bra.

Sara shared photos of her outfit to social media after she says this all went down ... and, we gotta say it's not super risqué ... certainly more coverage than a swimsuit would provide. Plus, given what's allegedly gone down on some flights recently, showing a little cleavage ain't such a big deal.

Cheek was shocked and totally humiliated in front of the other passengers ... some of whom she says were wearing very similar outfits to hers.

Sara says she wears this kind of outfit all the time when she travels -- it's perfect for getting a quick workout in on the go, she explains -- and, no one has ever spoken to her before about her look.

Of course, Cheek admits she doesn't look like everyone else in a sports bra -- she says her big boobs make her stand out -- and, she ultimately feels the dress code isn't being enforced across the board.

Put into simple words ... Sara says she was targeted 'cause she's white and blonde with a big ol' rack!!!