

This is because the air density is higher closer to sea level than it would otherwise be at higher elevations.

The airport has been criticised in recent years for overcrowding and delays.The airport holds a Civil Aviation Authority Public Use Aerodrome Licence, which allows flights for public transportation of passengers or for flying instruction.Heathrow Airport has Anglican, Catholic, free church, Hindu, Jewish, Muslim and Sikh chaplains.In the 1950s, Heathrow had six runways, arranged in three pairs at different angles in the shape of a hexagram with the permanent passenger terminal in the middle and the older terminal along the north edge of the field, and two of its runways would always be within 30° of the wind direction.Policing of the airport is the responsibility of the aviation security unit of the Metropolitan Police, although the army, including armoured vehicles of the Household Cavalry, has occasionally been deployed at the airport during periods of heightened security.Night-time flights at Heathrow are subject to restrictions.Heathrow Airport is used by over 90 airlines flying to 170 destinations worldwide.

Facts about London Heathrow Airport (LHR):
