It is Which Travel that is behind the survey.
Passengers gave the airline the lowest possible character in boarding, comfort, flight cabin terms and food and drink.
Ryanair thus ended a customer satisfaction of only 40 percent in the survey.
There were particularly canceled flights, baggage rules constantly changing and delays that caused passengers to feel frustrated.
Thousands replied that they would never fly with Ryanair, even though the company is cheaper than its competitors.
Singapore Airlines came out of the survey best, with a score of 85 percent.