[3] The new terminal was built south of the southern runway at a cost of £200 million over an 197 acres (80 ha) site.

Upon opening, it boasted other innovations including the complete segregation of arriving and departing passengers and a departure concourse over 1⁄3 mile (0.54 km) long.

Terminal 4's distance from the CTA and design were ill-suited for British Airways' long-haul operations.

Passengers' baggage also had to make the trip by van, sometimes resulting in the luggage being mislaid, although this problem was somewhat alleviated in the late 1990s by the construction of an automated transfer tunnel between the CTA and Terminal 4.

The departures forecourt has been upgraded to reduce traffic congestion and improve security and an extended check-in area opened in late 2009.

[10] Three Oneworld members fly out of Terminal 4, Malaysia Airlines, Royal Air Maroc and Qatar Airways.

The Piccadilly line has up to six trains per hour (about every 10 minutes) in the direction of Cockfosters via central London.

Trains to central London run via Heathrow Terminals 2 & 3 tube station.

Although the journey takes longer, fares are much cheaper than on the Elizabeth Line and Heathrow Express services.