France's Vinci is paying about 2.9 billion pounds ($3.7 billion) for a majority stake in Gatwick, adding the second busiest airport in Britain to its portfolio despite the shadow of Brexit.
Expected to close by June next year, the deal to acquire a 50.01 percent stake would make Gatwick the single largest asset in Vinci's airport network, which would grow to 46 airports spanning 12 countries, the French company said on Thursday.
"The transaction represents a rare opportunity to acquire an airport of such size and quality," it said in a statement.
Vinci has been expanding into faster growing and more profitable concessions such as airports and motorways, as well as in engineering projects for the energy industry, to counter signs of weakness elsewhere in the construction sector.
The French group is investing despite short-term uncertainty about the impact on travel of Britain's departure from the European Union at the end of March.
Gatwick made unwelcome headlines last week after drone sightings caused 36 hours of travel chaos for more than 100,000 Christmas travelers.
Gatwick Chief Executive Stewart Wingate, who will remain in his role, said the airport was learning lessons to avoid a repeat of the disruption.