Spanx founder Sara Blakely and Heather Thomson — who’s behind rival shapewear line Yummie Tummie — are at war over trademarks, and their husbands were unwittingly drawn into the dispute when they happened to be seated next to one another on a plane. Thomson, who appeared on “The Real Housewives of New York City,” claims Spanx ripped off her designs for a control-top tank top, but Spanx on March 5 filed a complaint arguing Thomson’s patents aren’t valid. We’re told that the following weekend, Thomson’s husband, lawyer Jonathan Schindler, sat next to Blakely’s husband, Jesse Itzler, on a flight from Tampa to New York. Sources said the two spoke of their New York and Florida roots, when Schindler realized who Itzler was. “Your wife and Spanx filed a lawsuit trying to invalidate my wife’s patent,” Schindler was overheard saying. Itzler responded, “Oh, she’s probably not even aware of it.” The two continued chatting despite the awkward moment. Schindler even told Itzler, “I hope when this is all over we can all get together.”