Tim Alderslade, chief executive of Airlines UK, has requested "urgent answers" from transport secretary Grant Shapps over the UK government’s traffic light system decision-making process.
It comes following yesterday’s (3 June) announcement that Portugal was to be moved to the amber list and no countries were to be added to the green list.
Another seven countries, meanwhile, were placed on the government’s red list, including Egypt and Sri Lanka.
Alderslade has since written a letter to Shapps with a series of questions about the methodology used to determine a country’s status in regards to the opening of international travel.
Alderslade said: "The decision was both a shock and severe blow to the UK aviation industry and the travelling public.
"We request urgent answers as we approach rapidly the critical summer period on which tens of thousands of UK travel and tourism jobs depend."
In the letter, he asked Shapps why Portugal was not placed on a ’green watchlist’ - a protocol promised by the Global Travel Taskforce as a means to provide more clarity for travellers - and when the UK could see the implementation of such a list.