A THIRD runway at Heathrow airport will pave the way to better timed and more frequent flights between the hub and Scotland's three busiest airports after a decade of declining access, bosses have said.

Heathrow chiefs will today announce a package of measures designed to help support routes from Scotland, including a review on how to reduce airport charges to help boost domestic services to and from Europe's busiest hub airport.

If Heathrow is given the go-ahead to expand from two to three runways, the revised airport charges will be implemented from January 1, 2016.

Independent research commissioned by Heathrow and undertaken by the planning consultancy, Quod, estimated that a third runway at the hub would deliver £14 billion in economic growth for Scotland by 2050 and more than 16,000 jobs north of the Border - four times as many as a second runway at Gatwick.

A spokesman for the Scottish Chambers of Commerce said: "Our priority is to ensure that investors around the world have access to Scotland and to strengthen our businesses' ability to compete for global growth.

"This plan will deliver more jobs for our region, boost our economy and ensure Scotland continues to grow as an attractive place to live and work."

The Scottish business community and travellers have been increasingly cut off from Heathrow over the last 10 years as airlines prioritised limited slots for more lucrative long-haul services at the expense of Scottish routes.

The average number of daily flights departing from Scottish airports to Heathrow has declined from 50 in 2005 to 35 today. The loss of the Virgin Little Red services from Aberdeen and Edinburgh by the end of September of this year will decrease that to just 26 daily departures, all operated by British Airways.

High landing charges at the airport were partly blamed for the demise of BMI in 2012, which had a crippling effect on Glasgow connections to Heathrow.

It comes after a recent OECD report warned that higher airport charges likely to result from an expanded Heathrow would "discourage high frequency, low capacity feeder flights".

The airport is also vowing to create a £10 million Route Development Fund to provide start-up capital which will allow airlines to operate five new routes for three years.

Overall, the third runway would mean "better timed and more frequent flights" between Glasgow, Edinburgh and Aberdeen, said Heathrow bosses.Heathrow connects to 75 destinations worldwide that are not served by other airports in the UK, with links to growing economies in the far East and South America particularly sought after by business.

Scottish Chambers of Commerce and the Scottish Council for Development and Industry (SCDI) have both backed Heathrow's expansion over Gatwick, while budget carrier Easyjet has said that extra capacity at Heathrow would enable it to launch a direct connection with Inverness.

A consultation ended in February and the Airports' Commission, chaired by Sir Howard Davies, is due to publish its final report this summer, after the General Election.

Critics have accused ministers of kicking the controversial issue into the long grass, with Willie Walsh, chief executive of BA owner IAG, warning that it was a "lost cause" that no Government would have the bottle to carry out.

Heathrow chief executive, John Holland-Kaye, said its commitments "show that we have a plan to deliver what Britain needs".

"Only Heathrow can connect Scotland to global growth. Let's get on with it," he said.

Mike Cantlay, chairman of VisitScotland, said the measures were "potentially hugely significant for international travel to Scotland".

However, industry sources suggested the Route Development Fund was unlikely to provide "real money" to airlines - something highly problematic under EU competition rules - but would instead boil down to a sum total of discounted landing charges to help the new services off the ground.

A spokesman for Gatwick also stressed that the Institute of Directors, which favours expansion at both airports, believes a second runway at Gatwick would favour regional destinations.

A spokesman for Gatwick said: "Scotland should not be swayed by empty promises. Gatwick already serves more regional destinations than Heathrow where domestic services have been progressively cut back.

"Heathrow has made many promises in the past but like other significant pledges made by the company, it will likely come to nothing."

Transport Minister Derek Mackay said the Scottish Government remained impartial but called for a "defined minimum level of access for flights from Scotland to ensure we adequately benefit from any new capacity".