JetBlue: Go for it on all JetBlue flights.
Delta: FAA approval for Delta mainline domestic flights only. They expect Delta Connection flights to have the thumbs-up by the end of the year.
American: Good for all American mainline flights and American Eagle. If the flight is operated by a regional partner like SkyWest, ExpressJet, Republic or Chautauqua, then it does NOT yet have FAA approval.
United: They're calling it "offering electronics-friendly cabins." So far the FAA approval is only for United domestic mainline flights, not yet on United Express.
US Airways: Only for US Airways domestic mainline flights, not yet on US Airways Express.
Alaska Airlines: Only for Alaska Airlines mainline flights. Approval for flights operated by Horizon Air and SkyWest is expected next week at the earliest, end of year at the latest.