Various reports have been filtering through the Internet since a failed terror attack in Detroit, MI on Christmas Day, that there has been some major clamping down on security.
People have reported online there have been more pat-downs and some airlines are enforcing stricter restrictions on flights. This includes, on some flights, bans on all electronic items during the flight. The Transportation Security Administration of the US Government said:
Passengers flying from international locations to U.S. destinations may notice additional security measures in place. These measures are designed to be unpredictable, so passengers should not expect to see the same thing everywhere.
You may be lucky and find that your airline doesn't have this ban in place, but be sure to have a book on hand in case your DS is banned on that long, long flight!