Have you ever thought about the process it takes for a plane to fly or land? By the time the passengers are deplaning or boarding, the engines are normally off even if the plane had just landed twenty minutes earlier. Before the plane takes off, the pilot(s) go through intensive pre-flight processes before they can confirm they are ready for take off (again). In short, by the time the plane is ready to lift off from the ground to the air, alot happens in between.
Transition takes place.