Image copyright Peter Whatley

Aberdeen, Glasgow and Southampton airports have been sold by owners Heathrow Airport Holdings (HAH) in a £1bn deal.

The three airports will now be owned by a consortium formed by two companies - Spanish firm Ferrovial and Australia-based Macquarie.

The sale is expected to be completed in January of next year.

The three airports will be managed locally but supported by Ferrovial's and Macquarie's shared ownership.

Ferrovial already part-owns Heathrow, the UK's busiest airport, and holds a 25% stake in HAH, which was previously known as BAA.

The deal means HAH will now operate only its flagship London hub.

The company had previously operated seven airports but an inquiry by the Competition Commission ordered it to be broken up.

By the time of the ruling it had already sold Gatwick, before later disposing of Edinburgh and announcing the sale of Stansted last year.

Douglas Fraser

BBC Scotland business and economy editor

The sale of Glasgow, Aberdeen and Southampton airports has been some time coming. Since the competition regulator took aim at the formerly nationalised British Airports Authority, later BAA plc, the break-up of that empire has looked likely.

Gatwick was sold five years ago for £1.5bn, and is now fighting hard to get the planning nod for a new runway, instead of letting Heathrow expand.

Either Edinburgh or Glasgow had to be sold, BAA was told, so the capital's airport went to the same infrastructure investors who own Gatwick for a whopping £807m.

Renaming itself Heathrow Airport Holdings plc, the parent company then had to shed Stansted, going for £1.5bn to council-controlled Manchester Airport. And that left the three smaller parts of the company awaiting their fate.

The uncertainty over ownership has not been helpful for them. New owners may be willing to invest in upgrading Aberdeen's facilities, while helping Glasgow compete more effectively with both Edinburgh, its new rival, as well as the beleaguered Prestwick. But then, those investors will also want a return on their billion pounds.

Heathrow itself is 25% owned by Ferrovial with other stakes controlled by investment vehicles from Qatar, Quebec, Singapore, the US, and China.

Heathrow chief executive John Holland-Kaye said: "This sale enables us to focus on improving Heathrow for passengers and winning support for Heathrow expansion.

"Heathrow is the UK's only hub airport, connecting the whole of the UK to the world and bringing economic benefits locally and nationally."

Edward Beckley, Macquarie's European head, said the firm had a "long and successful track record of investing in and developing airports around the world".

He added: "We look forward to working with these airports over the long term to support route growth and enhance the passenger experience for the communities they serve."

Ferrovial chief executive Inigo Meiras said: "We are committed to improve these facilities and their services looking to a better passenger experience and in order to grant access to further domestic and international destinations."

Glasgow is the eighth busiest of the UK's airports, with 7.4m passengers and 104,000 aircraft movements in 2013.

Aberdeen is 14th busiest, with 3.4m passengers and 73,000 aircraft movements.

Southampton is 18th busiest with 1.7m passengers and 36,000 movements.

Amanda McMillan, managing director of Glasgow Airport, said: "Clearly this is a landmark day for Glasgow Airport and whilst we will be sorry to leave the Heathrow group, we do so knowing we're in an extremely strong position.

"We have benefited from considerable investment in recent years and have achieved a great deal of success in securing new routes and growing passenger numbers. Together with my team, I am looking forward to working with Ferrovial and Macquarie to further develop our airport and ensure it continues to deliver for Glasgow and Scotland."

Carol Benzie, managing director of Aberdeen Airport work on the deal had been taking place behind the scenes for several months.

She added: "Locally things remain very much business as usual. Our passenger numbers continue to grow, and we will continue to operate as we have been with a focus on the safety and security of our customers, as well as on delivering an excellent standard of customer service.

"No changes to the way we operate are planned and we will keep striving to deliver on all our commitments in the run up to a formal handover by the end of the year."

The deal was welcomed by local authorities, with Glasgow City Council leader Gordon Matheson saying: "Glasgow Airport is of huge strategic importance for the city and the west of Scotland with over 5,000 jobs dependant on its continued success.

"Its success is vital to ensure that Glasgow and our city region continues to be an attractive location for investment and for local businesses to expand overseas.

"I'm encouraged to see that this deal is backed with a wealth of experience in both the air industry and public infrastructure - and my council will continue to work in close partnership with our airport to ensure it meets the needs of local business and leisure travellers."

Mark Macmillan, the leader of neighbouring Renfrewshire Council, said the deal would give Glasgow Airport "security of ownership and more certainty for the future".

Glasgow Chamber of Commerce chief executive Stuart Patrick said: "The existing management team has done an excellent job in promoting the airport's assets and attracting in new flights over what have been rough times. There is still huge potential for growth and route development, and that has obviously influenced the attractiveness of Glasgow as an investment."