The terminal is used by all Star Alliance members currently operating at Heathrow (consolidating the airlines under Star Alliance's co-location policy "Move Under One Roof") with the exception of Air India which operates out of Terminal 4. Aer Lingus, Little Red (Virgin Atlantic's domestic operations) and Germanwings also operate out of the terminal. The airlines moved from their original terminals in phases over a period of six months with only 10% of flights operating in the first six weeks (United Airlines' transatlantic flights to Heathrow) to avoid the opening challenges witnessed at Terminal 5.
The original Terminal 2 building was the airport's oldest terminal, opening as the Europa Building in 1955. It had an area of 49,654 m2 (534,470 sq ft) and was designed to handle around 1.2 million passengers annually; in its final years of operation it often accommodated around 8 million. A total of 316 million passengers passed through the terminal in its lifetime. The terminal was demolished in 2010,and the site was combined with that of the Queen's Building to form the new site.