Ryanair has been voted the worst short-haul airline in the UK by passengers for the sixth year running.
Passengers polled by the consumer guide gave Ryanair the lowest possible rating for boarding process, seat comfort, food and drink offering, and cabin environment.
Thomas Cook Airlines with a 52% customer score and Wizz Air with 54% rated second and third-worst in the survey.
According to Which?, Ryanair is also the airline most British passengers say they're now boycotting. Of survey respondents who named an airline they'd never fly with, 70% said Ryanair.
In 2018, thousands of Ryanair passengers suffered disruptions as strike action forced the airline to cancel flights. The airline has since refused to offer those passengers compensation, resulting in legal action from the UK's aviation watchdog.
In October, Ryanair was heavily criticised for failing to remove a racially abusive passenger from a flight.
Responding to the Which? survey results, a Ryanair representative told the BBC: "Ryanair passenger numbers have grown by 80% in the past six years and Ryanair.com has become the world's most visited airline website. These facts reflect what customers want much more than an unrepresentative survey of just 8,000 people."
Guernsey-based carrier Aurigny Air Service finished top of the short-haul pile with a customer score of 81%, followed by Swiss Airlines with 80% and Jet2 with 75%.
Ryanair's major rival EasyJet finished 11th with a 63% customer score. British Airways finished 15th with a 56% customer score.
Which?'s travel editor Rory Boland said of the results: "Air fares might seem to be getting cheaper, but only if you don’t fancy sitting with your family and children or taking even a small cabin bag on board. Increasingly you need a calculator to work out what the final bill will be, especially with Ryanair."