London City Airport has been bought by a consortium led by a major Canadian pension fund.
The price paid has not been disclosed, but the airport's value has been put at about £2bn.
City Airport, which is near Canary Wharf in London's Docklands, is popular with bankers and City professionals because of its proximity and its small size.
Last year, a record 4.3 million passengers used the airport.
The deal involves Alberta Investment Management Corporation, and investment funds the Ontario Teachers' Pension Plan and Wren House, part of the Kuwait Investment Authority.
They already own a string of airports, including Belfast International Airport, Birmingham Airport, Bristol Airport, Brussels Airport and Copenhagen Airport.
They described London City as "a highly attractive infrastructure investment in the UK".
"The airport represents a unique opportunity to invest in an integral part of the London airport system and offers a service proposition based around location, convenience, speed and customer service".
It promised to increase the number of routes it flies and said it would have a "positive economic impact for all of London and the local community, in particular".
London City was last bought in 2006 by Global Infrastructure Partners, when it carried two million passengers a year.