It came as Nicola Sturgeon announced Scots would be allowed to travel to the same 12 countries without the need to quarantine on their return as those in England – albeit several currently bar visitors.
They are: Portugal including the Azores and Madeira, Israel, Australia, New Zealand, Singapore, Brunei, Iceland, Faroe Islands, Gibraltar, Falkland Islands, South Georgia and the South Sandwich Islands, and St Helena, Tristan de Cunha and Ascension Island.
The Scottish Government said the list “will be subject to review based on Scotland’s specific needs”.
Travellers will need to take a PCR Covid test after arrival home but will not need to self isolate.
Ryanair responded by announcing 19 flights a week on routes to Faro, Porto and Lisbon from Edinburgh, Aberdeen and Prestwick from May 24.
The First Minister said that despite the relaxation, Scots were advised to holiday at home this year, which drew criticism from business leaders.
She said: “We still intend to be highly cautious on international travel, given the risk of new variants, but we consider that the situation now allows us to begin a careful move away from blanket restrictions on non-essential travel.
"Everyone should think seriously about whether they really need to travel abroad this summer.
"I know for many people international travel is about family connections.
"But when it comes to holidays abroad, my advice continues to be to err on the side of caution and to staycation this summer.”
The Scottish Passenger Agents’ Association (SPAA), which represents travel agents, said it anticipated more airlines would add extra flights to Portugal after British Airways announced Edinburgh-Faro services, as The Scotsman revealed last Thursday.
Within hours, Ryanair announced between three and seven flights a week from Edinburgh to Faro, Porto and Lisbon, and three a week from Aberdeen and Prestwick to Faro.
Easyjet, Scotland’s largest airline, last week said it would add flights from Edinburgh to Lisbon and Gibraltar, Glasgow to Faro.
SPAA president Joanne Dooey said: “The inclusion of Portugal on this list is very significant and important for Scotland.
"It’s one of the most popular holiday destinations for Scots, ranking in the top choices along with Spain, Greece and Turkey.
“We expect to see airlines and operators transferring any spare capacity to flights to Portugal this summer, and consequently travel agents across Scotland are ready to advise travellers and to help them to make their plans safely.”
But Ms Dooey added: “PCR tests remain an expensive option, particularly for those travelling as a family group.
"Our position remains that the cost of testing – particularly the requirement for a PCR test for each traveller on return to the UK – is too high and that affordable testing in the form of antigen and lateral flow is needed.”
Scotland’s three largest airports described Ms Sturgeon’s decision as a "missed opportunity”.
AGS Airports, which runs Glasgow and Aberdeen airports, issued a joint statement with Edinburgh Airport in which they also called for more information from the Scottish Government.
They said: "Whilst removing the travel ban is a step in the right direction, it is very much a missed opportunity with so few countries making it onto the green list.
"We are again in the position of being a week away from a major change to operations and are waiting on details of how the Scottish Government wants this to work and how it will be managed.
"We appreciate there are many things to consider, but we encourage the Scottish Government to work with us on making testing more affordable rather than it being a barrier for those who need and want to travel.
“The Scottish Government must also be very clear about when and how we can encourage visitors from green list countries to try and save the thousands of jobs in Scotland that depend upon international travellers.”
Scottish Chambers of Commerce chief executive Liz Cameron described the First Minister’s announcement as a long-awaited “important first step towards the wider restart of international travel in the coming months”.
She said: “Confirmation of a four-nations approach is welcome and will help to avoid confusion for customers and operators, as well as any competitive disadvantage if there was divergence between Scotland and rest of the UK.
“However, the continued government advice on avoiding international travel will harm the tourism industry.
"Business support should be provided for the expected loss of trade and most importantly, we urge the Scottish Government to work with industry to kick start international travel safely.”
The British Air Line Pilots Association (Balpa) accused Ms Sturgeon of taking the wrong approach.
General secretary Brian Strutton said: “She thinks there has to be a good reason for adding a country to the green list.
"No, there needs to be a good reason to keep a country off it.
“This mindset needs to change.
"Our vaccination programme is going exceptionally well, and people are desperate to take advantage of their jabs and jet off.
“Countries like the US, where vaccination rates are very high, should be opened up immediately and others should be opened as soon as possible.
“Amber and red [where self isolation and quarantine hotel stays are required, respectively] should only be used when there is a good reason to stop people from travelling – they should absolutely not be the default option.”
The Airport Operators Association described today’s decision as a “big step forward for Scotland”.
Chief executive Karen Dee said: ”The Scottish Government’s decision to take a similar risk-based approach as the UK Government is also a vital step to ensuring a four-nation approach as travel restarts.
“Yet despite today’s announcement and Scotland’s successful vaccine rollout, a meaningful restart of aviation is not yet possible because there are so few countries on the green list.”