Ryanair has been voted the world's least liked airline because of cramped seating, unfriendly staff and delays.
Many passengers are more concerned about legroom than price
Online travel service TripAdvisor said it polled 4,000 of its users on a range of subjects from airlines and airports, to worries and holiday hotspots.
Ryanair was not the only low-cost carrier singled out for criticism, with Easyjet voted the second worst. British Airways was picked as the best airline.
Ryanair countered that it consistently topped customer-service indicators.
A spokeswoman said that Ryanair expected to carry 42 million people this year, "so we must be doing something right".
"Ryanair carries more UK passengers than any other airline because it has both lowest fares and the best punctuality and its passengers ignore irrelevant and baseless surveys," the company said.
"The public votes with its feet."
Despite its growing business and role in revolutionising the way Europe's air industry has operated, Ryanair has often also proved a controversial company.
Chief executive Michael O'Leary has been an outspoken critic of rivals and the industry, while his staff have previously complained about low wages, overwork and having to pay for their own training and uniforms.
Among the other topics covered in the poll by TripAdvisor, Heathrow was voted the world's worst airport. Changi in Singapore topped the survey.
Travellers were most worried about terrorism, while bird flu and natural disasters were also concerns, TripAdvisor said.
The company identified the hottest emerging holiday hotspots as Pamukkale in Turkey, Parga in Greece, and Ayr on Scotland's west coast.
"Home of the eponymous race course, Ayr can brace itself for a major influx of visitors from around the world next year," TripAdvisor said.