Two options to provide a rail link between Glasgow city centre and Glasgow Airport have been announced.
A tram-train and a light rail link have been put forward, with the former considered to be the best-performing option offering the best value for money.
The business case for both options has been developed jointly by Renfrewshire Council and Glasgow City Council.
It will be put before councillors in both authorities before going to the Glasgow and Clyde Valley Cabinet for approval in December.
If approved, further work would be done to develop more detail on both options before a final, preferred choice is made next year.
Under the tram-train option, tram-train carriages would operate on the heavy rail network between Glasgow Central Station and Paisley Gilmour Street, before moving on to new tram rails running between Paisley and the front of the airport terminal building.
This would offer a 16.5-minute direct journey between the city centre and the front door of the airport.
The estimated cost is £144.3 million while construction could start in 2021 and the service could be operational by 2025.
A £102 million light rail personal rapid transit system is also being considered. In this scheme, passengers would travel by standard train to Paisley before disembarking and changing onto a new light-rail system to complete their journey to the airport.
The rail connection between Glasgow city centre, Paisley and Glasgow Airport is the flagship project in the £1.13 billion Glasgow and Clyde Valley city deal - a funding agreement between the UK Government, the Scottish Government and eight local authorities across Glasgow and the Clyde Valley.
It comes after previous proposals for a rail link between the city and airport were scrapped in 2009 amid public spending cuts.
Councillor Frank McAveety, leader of Glasgow City Council, said: “Glasgow and the Clyde Valley is the economic powerhouse of Scotland and Glasgow Airport plays a crucial role in the continued growth of the region.
“We’ve long argued that a new rail link between the airport and the city centre is essential for the thousands of tourists and business travellers who fly into and out of Glasgow every day.
“The airport already supports thousands of jobs but this new rail link, which is the single biggest element of our city deal, will be the catalyst that takes us to a new level, vastly improving the customer experience and generating even more jobs and inward investment.”