Planes can get delayed for numerous reasons. Mechanical issues, weather, air traffic, flight crew scheduling issues and more can all be potential causes for a delay. If a delay is weather related, air traffic control might need to wait until winds and visibility are at safer levels before they can allow the plane to take off. Mechanical issues can cause delays due to the need to find and fix any problems before the airplane can safely leave the ground. Flight crew scheduling can cause delays if crew members are late or not available. Finally, air traffic delays can occur when there are too many planes flying in a certain area at the same time.