Prestwick Airport is looking for a new chief exceuctive after the departure of Iain Cochrane last Wednesday.
The Scottish Government owned airport has so far received £40m in loans after being bought for a £1 in 2013.
Mr Cochrane is set to depart the airport at the end of September after 20 years, including five as chief executive.
Chairman Andrew Miller, who was appointed in November last year said Mr Cochrane’s departure was due to changes which “required new vision, leadership and expertise in the executive team.”
Chief commercial officer Graeme Sweenie is also to leave Prestwick at the end of this month.
Andrew Miller said: “The future of Prestwick is likely to be quite different from the past.
“The business model needs to be both re-designed and delivered rapidly so the airport can look forward to a profitable, sustainable future.”
However, the Hamilton-born former Air New Zealand executive said there were no plans to reduce the workforce, which peaks at 310 in the summer.
Mr Miller said plans included trying to re-establish London flights, perhaps to City airport, with Flybe a possible carrier.
Mr Miller said: “I firmly believe Prestwick can return to prosperity, but there needs to be a radical turnaround in the business in order to achieve that.
“The business can be fixed. I would not have taken it on otherwise.”
However, he said it would take around two years to “lessen the impact on the public purse” - and longer to get the airport back into profit.
He said both departing executives “have given Prestwick many years’ committed service.”
Mr Miller said recently-appointed non-executive directors would assist remaining managers until successors were found.
Mr Cochrane said: “It has been my huge privilege to lead this fantastic airport with its exceptional and committed staff, but it’s time for a change.”