High Quality Content by WIKIPEDIA articles! British Airways (BA) is the flag carrier airline of the United Kingdom, based in Waterside, near its main hub at London Heathrow Airport. British Airways is the largest airline in the UK based on fleet size, international flights and international destinations. BA`s UK passengers originating at non-London airports must connect via London after British Airways discontinued all direct overseas flights from UK airports outside London following the sale of BA Connect to British regional carrier Flybe in 2007.