Easyjet has been named the airline with the most delays and cancellations so far this year, followed closely by Ryanair.
Ryanair dismissed the figures as "bogus".
Adeline Noorderhaven from compensation company EUclaim helped compile the figures, and said passengers were being left frustrated.
"They're not being provided with information, nor with re-routing at the earliest opportunity, and that's causing frustration and the large amount of complaints we're getting." she said.
Ryanair has rounded on the company, calling them "ambulance chasers" whose data doesn’t stand up.
In a statement, the airline said: "We do not believe any statements made by ambulance chasers like EUclaim, who charge excessive fees for the non-existent service they claim to provide, and whose "internal data" is totally unsubstantiated.
"Given that Ryanair carried over 55m customers in the first half of 2016 even these bogus figures (Ryanair received just over 500 claims from this company which is an average of 1 for every 110,000 passengers carried) show just how satisfied Ryanair's customers have been."