Most ground services are not directly related to the actual flight of the aircraft and instead involve other tasks. The main categories of groundhandling services are described below. In aviation, aircraft ground assistance defines the maintenance of an aircraft while it is on the ground and parked (normally) at a terminal gate of an airport. Many airlines subsource ground handling at airports, assistance agents or even another airline. According to the International Air Transport Association (IATA), airlines relocate, according to conservative estimates, more than 50% of ground handling at airports around the world.  Ground handling addresses the many service requirements of a commercial aircraft between arrival at a terminal gate and departure time on its next flight. The speed, efficiency and accuracy of groundhandling services are important to minimize transit time (the time the aircraft must remain parked at the door).  Faster rotations for lower ground periods are correlated with better gains.  Catering includes unloading unused food and beverages from the aircraft, as well as loading fresh food and beverages for passengers and crew. Airline meals are usually delivered in air service trolleys. Empty or garbage-filled trolleys from the previous flight are replaced by fresh trolleys.
Meals are mainly prepared on the ground in order to minimize the amount of preparation (with the exception of cooling or reheating) in the air. Airlines with less frequent service or fewer resources at a given site sometimes outsource groundhandling or aircraft maintenance at the request of another airline, as this is a cheaper short-term alternative to setting up groundhandling or maintenance capabilities. Commons: Ground Handling – Wikimedia Commons airlines can participate in an Industry Voluntary Assistance Agreement (MAGSA). Magsa is published by the Air Transport Association (the current version dates from 1981) and is used by airlines to determine aircraft maintenance and assistance prices at MAGSA fares, which are updated annually based on changes in the U.S. Producer Price Index.