Airline passengers on Long Island and across the country dealt with some unsettling news Thursday.The Federal Aviation Administration (FAA) announced that four U.S. airlines are being investigated for not following federal aviation regulations. Officials said three of the unnamed airlines didn't meet inspection deadlines and that the fourth didn't submit a required plan.At MacArthur Airport, flyers said the news was upsetting since they didn't know which airlines were being probed. Some passengers said they were more nervous about flying, but wouldn't let it alter their plans.FAA officials said the public should still feel safe to fly despite the maintenance investigations.