The operator of Aberdeen Airport has hit out at the "unpredictable" decisions being made on quarantine rules in Scotland.
The Scottish Government has reversed its decision to relax quarantine rules on travel from Spain after just three days.
The decision - which has also been taken by the UK Government - comes after a rise in coronavirus cases there.
Aberdeen Airport previously said trips to Spain accounted for around two-thirds of its summer leisure business.
In a statement today, Derek Provan, chief executive of AGS Airports - which runs Aberdeen, Glasgow and Southampton - said: "While we understand that public safety must always come first, the resumption of blanket quarantine measures for those travelling to Spain is a hammer blow and could not come at a worst time.
"This decision clearly highlights the need to have robust testing measures in place that will deliver confidence for our passengers and airline partners while providing the necessary assurances for both the UK and Scottish governments.
"There is simply no way we can operate in such an unpredictable environment, where decisions regarding one of the UK’s most important tourism destinations change by the week - we must have consistency.
"The aviation industry is facing unprecedented challenges, which is evident in the thousands of jobs already lost and the many more that continue to remain at risk."
Justice Secretary Humza Yousaf said: "The decision to exempt Spain earlier this week, was taken when the data showed there was an improvement in the spread of the virus. But clearly the latest data has given us cause for concern to overturn that decision.
"We appreciate that this will be disappointing. However, we have always been clear we are closely monitoring the pandemic situation in all countries and that we may require to remove a country from the list of places exempt from quarantine requirements should the virus show a resurgence.
"It is still active and it is still deadly. Suppressing the virus, preventing it from being transmitted and protecting public health is our priority."