An undisclosed number of expressions of interest to acquire the South Ayrshire complex were received by the deadline on Monday.
Officials said these would be evaluated. Up to three of the bidders are due to be asked at the end of next week to lodge full offers.
The preferred bidder is due to be selected around 6 September and the sale completed around 4 October, according to the sale documents.
Ministers have always said the debt-ridden airport would be returned to the private sector after they bought it for £1 in 2013 to avert closure and save hundreds of jobs.
However, the sale announcement last month came as a surprise since several businesses have expressed interest in buying it over the past few years.
The Scottish Government has insisted it has not already lined up a buyer and is not going through the formal sale process just to follow official procedures.
But its spokesman would say only: “The deadline for submitting expressions of interest has now passed and submissions received will now be evaluated. To protect the integrity of the process, we will not be making any further comment and will update parliament at the appropriate time.”
The spokesman refused to clarify whether a buyer would have to repay the £39.9 million of Scottish Government loans pumped in so far to keep the airport going.
The sale documents state that evaluation of offers would include ”the price offered for the shareholding in PAHL [airport owner Prestwick Aviation Holdings Limited] on a debt free cash free basis (to be applied in repayment of the Scottish Government loan first)”.
One respected aviation analyst was sceptical about whether a sale of the 880-acre site could be secured.
John Strickland, of JLS Consulting, said: “In my view, it is likely to prove challenging to find a buyer for Prestwick given intense competition from Glasgow and Edinburgh and a slowing economic outlook.”
Ryanair is the airport’s sole remaining airline, flying some 670,000 passengers in the year to March, the airport’s lowest for 20 years. It compares to Glasgow’s total of nearly ten million and Edinburgh’s 14.3 million in 2018.
However, Prestwick is expanding cargo and military flights, and hopes to be licensed as a spaceport for horizontal launches, and become a logistics hub for the expansion of Heathrow.