Plane Meltdown as Passenger Freaks Out, Accused of Being Possessed by Devil

When your quick flight turns into an 'Exorcist' sequel -- that's how you can describe this bizarre scene of a woman having an epic meltdown, leaving her fellow passengers to wonder ... WWJD?!? This all went down on a Frontier Airlines jet traveling from Houston to Denver, but the flight had to stop off in Dallas after the troubled passenger started wailing like her leg was cut off ... stirring a huge disturbance. Nobody seems to know what exactly was …