Sen. Susan Collins, a Maine Republican, and fellow GOP senators accused the Obama administration of creating a "manufactured crisis" by furloughing FAA air traffic controllers and causing delayed flights. J. Scott Applewhite/AP hide caption

itoggle caption J. Scott Applewhite/AP

The current radar-based air traffic control system (shown here) will eventually be replaced with a new system called NextGen, which will rely on GPS. A number of computer security experts are concerned that NextGen is insecure and vulnerable to hackers. John Moore/Getty Images hide caption

itoggle caption John Moore/Getty Images