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.
Details surrounding the criteria and thresholds that determine a country’s tier allocation were also questioned, as well as the reasoning behind the exclusion of some countries from the green list which have low case rates.
"Will the government publish transparent country data? What is the UK’s equivalent number to the EU’s proposed level of 75 cases per 100,000 people to allow non-essential travel?
"On what scientific grounds are fully vaccinated customers still being subject to the same level of restrictions as non-vaccinated arrivals in the UK?
"Is there a pre-determined level of vaccination rate set before a country is able to gain green status?"
The news that Madeira and the Azores were amber-listed prompted the question: "What datasets are being used to assess islands separately from their mainland territories?"
The rules surrounding genome sequencing were also brought forward.
Alderslade added: "It is clear from the actions this week that the current traffic light framework established by the GTT does not reflect the risk of travel nor facilitate safe travel as it should, including by ignoring the proposal for a Green watchlist and given the absence of clarity on how country allocation criteria work in practice.
"If the government is serious about driving economic recovery, the framework must be adjusted by the latest at the checkpoint on 28 June, to provide a pathway for vaccinated people to travel without restriction, to remove restrictions for green countries and to make the amber category workable including reducing quarantine and the burden of testing on travellers."