An air trip for most passengers begins with a coach journey to the airport. The passengers then board the airplane, walking up steps or along ramps that lead directly to the doors. When all the passengers are aboard the airplane, the doors are hermetically sealed. The airplane then travels slowly, or taxis, to the point of take-off. During the entire time the pilot is in constant radio contact with the control tower.

The staff in the control tower is responsible for all the air traffic of the airport. When an airplane approaches the airport the control tower tells it which route to take and what speed to travel at. The radio messages between the airplane and the control tower are all tape recorded.

On departure, the flight crew of an airplane is provided with all the information necessary to navigate the route to their destination. They may feed the information into the airplane’s computer, which then controls the flight. The crew also checks with air traffic controllers by radio as they pass various points.

When visibility is bad the airplane is guided as it lands by an ‘approach control’ service that uses radar to show the pilot the way. Along the runways, which are usually hard-surfaced with concrete or asphalt, there are white lights and the end of the runway is marked by green lights. A line of blue lights shows the pilot the path he must follow after he has landed and red lights indicate obstacles and hazards to be avoided.