Stansted Airport is a medium-sized passenger airport with a single runway, located in the English county of Essex about thirty miles north of London. The airport is owned and operated by BAA. It is the third-busiest airport in the London area after Heathrow Airport and Gatwick Airport. Several budget airlines such as Ryanair and easyJet maintain bases at Stansted, and Volga-Dnepr often station a large Antonov An-124 freighter to the northwest of the main runway ready to carry outsize cargoes. FedEx is a dominant operator of trans-Atlantic freighter services.

The airport is named after the village Stansted Mountfitchet. The nearest town to the airport is Bishop's Stortford.

Tentative plans have been published for the addition of up to three more runways. If the Uttlesford district council approves the current plan, Stansted is to get a second parallel runway which should allow the airport to increase its capacity from 12 million in 2000 to 74 million air passengers in 2030. In 2004, the number of passengers using Stansted rose 11.7% to 20.9 million. As a comparison, traffic at Heathrow rose 6.2% to 67.1 million passengers, and Gatwick was up 5% to 31.4 million.

Stansted has a railway station below the terminal building, with frequent rail services to London and less frequent services to Cambridge and the Midlands. The Stansted Express train runs to and from Liverpool Street station in London every 15 minutes and the journey time is 45 minutes. At the time of writing (January 2004) the fare is 24 GBP or 36 EUR return.
Scheduled express bus or coach services run to and from Stratford, Victoria Coach Station, Liverpool Street Station and Golders Green (all in London), costing half as much as the train but taking rather longer. The bus/coach station is adjacent to the terminal building. National Express runs scheduled but infrequent direct coach services to the airport from Oxford as service JL757, taking about three hours, and hourly services to and from Cambridge.
Stansted is connected to northeast London and Cambridge by the M11 motorway and to Colchester and Harwich by the A120 dual-carriageway. The access from the motorway has recently been improved with a new grade-separated junction. The long term car park is situated about a mile from the terminal and passengers need to allow at least twenty minutes to park and use a courtesy bus shuttle service prior to check-in. There are short term car parks next to the terminal building.

Stansted International Airport has one terminal. The terminal facilities include a bureau de change, left luggage service, several shops and restaurants as well as internet access. Car hire and taxis can also be arranged from within the terminal building. The terminal building was designed by Foster Associates and features a "floating" roof, supported by a space frame of inverted-pyramid roof trusses. The base of each truss structure is a "utility pillar", which provides indirect uplighting illumination and is the location for air-conditioning and water, telecommunications, and electrical outlets. The layout of the airport is designed to provide an unobstructed flow for passengers to arrive at the short-stay car park, move through the check-in hall and on to the departure gates all on the same level. However, the airport has never catered for spectators or those wishing to watch friends depart.