The devices cannot be turned on during takeoff and landing, and at no time can these devices activate their internal radios on board the plane. That means that no calling or texting is permitted during takeoff, landing, or while in flight. The FAA is concerned that a radio signal from a mobile phone could interfere with readings used by the pilot to navigate and control the plane. A Charlotte attorney named Chad Tillman said that his smartphone was in Airplane Mode when he recorded the video.
Tillman was so annoyed by what he witnessed that as soon as he disembarked the plane, he wrote a strongly worded letter to American Airlines CEO Doug Parker. In the letter, Tillman said that he was worried that passenger safety was being jeopardized by the pilot’s action. American Airlines spokeswomen Andrea Huguely said that the pilot’s employer did talk to him about the texting, but did not say whether he was disciplined. Huguely never revealed the name of the airline that employs the texting pilot. The spokeswomen did add that, “If someone is concerned about what another passenger is doing, notify the flight attendant so they can address it when it happens.”
source: ClarenceMoore, CharlotteObserver via CNET