European airline Ryanair is under investigation by the advertising watchdog over a campaign which encouraged potential holidaymakers to "jab and go" following last month's rollout of the COVID-19 vaccine.
The carrier's Boxing Day promotion has attracted about 1600 complaints to the Advertising Standards Authority, which is now examining if rules were breached.
In the adverts, the airline said: "Covid vaccines are coming so book your Easter and summer holidays today with Ryanair."
It added that with a number of destinations on offer, customers "could jab and go".
Those complaining about the advert claimed it was misleading to suggest that a vaccine will be rolled out across the population by spring and summer and that there will be no travel restrictions.
Others claimed it was "offensive and irresponsible" and trivialised the impact of the pandemic.
The ASA has launched a formal investigation and will publish its findings in due course.
Ryanair did not respond to a request for comment.
Last year the regulator banned a Ryanair advert after over claims it had the lowest carbon emissions and was "Europe's low CO2 emissions airline".
The Irish carrier broke rules on environmental claims and misleading consumers in press, TV, and radio adverts, the ASA found.
Ryanair justified the adverts by saying its carbon emissions were lower than average.
Last month a row erupted between Ryanair and Britain's aviation regulator over rule changes imposed before Brexit.
The airline said it had been forced to close 12 domestic and international routes following a sudden crackdown on ownership rules.
The UK's Civil Aviation Authority hit back, saying it was incorrect to say suggest the policies had been changed at short notice.
The Telegraph, London