New plans for the state-owned Prestwick Airport will be drawn up if a buyer cannot be found - despite the deadline for bids passing more than a month ago.

Transport secretary Michael Matheson said offers for the airport were still being considered after the previously agreed October 4 timeframe.

Transport Scotland placed an advert inviting "expressions of interest" in Prestwick Airport in the Official Journal of the European Union earlier this year.

READ MORE: ScotRail criticised for ‘awful’ responses on Twitter

The airport passed into state ownership six years ago after it was threatened with closure following heavy losses.

A spokesman for Transport Scotland said the October deadline "was only ever indicative and intended as a guide for prospective buyers."

In a letter to rural economy and connectivity committee convener Edward Mountain MSP, Mr Matheson said “options were being considered” if the airport could not be sold, but efforts were being made to agree a deal.

He added: “Good progress continues to be made and we are satisfied with how the sale process is developing.

READ MORE: Labour calls for independent inquiry into CalMac ‘debacle’

"I have committed to providing an update to Parliament once I am in a position to do so, while respecting the need to maintain confidentiality for commercial reasons."

The airport was deemed a “strategic economic asset” when the Scottish Government purchased it for £1 in 2013.

However, in January it emerged debt owed to the government by Prestwick had risen to £38.4m from £30m.