This document provides an overview of airport components and operations. It describes landside areas like parking lots and roads, as well as airside areas such as runways, taxiways, and aprons. Runways are where planes land and take off, marked with white lines, while taxiways connect runways to parking areas and are marked with yellow lines. Aprons are where planes park. Airports can be towered or non-towered depending on air traffic. Heathrow Airport is located in west London, with 5 terminals and 1 cargo terminal, and was the busiest airport in Europe in 2011 for passenger traffic.