Having chased rf birdies, ground loop problems and feedback issues for over 30 years, I think it's interference between new graphics, MBA chassis and display input. Could even be P.S., fan, Airport, light sensor, or iSight that is feeding harmonics to display input. I seriously don't think it's the display on it's own. Or for that matter, any one piece. Just my cent and a half (not quite worth 2.)