Senior Ryanair executives told pilots in London last week that the company "grew too fast" and lost the trust of its pilots, but was working hard to restore it, the Irish Independent newspaper reported on Tuesday.

Ryanair shares have fallen over 10 percent since it announced on Friday it would recognize trade unions for the first time, a move that averted the first pilot strike in the company's history.

Pilots have demanded an overhaul of Ryanair's system of contracts and collective bargaining and some have spoken of a toxic atmosphere at the airline, Europe's largest by passenger numbers.

The relationship between the airline and pilots became "very inflamed" and "very tense" in recent weeks, Chief Operations Officer Peter Bellew told a meeting of Ryanair pilots at Stansted Airport near London, the Irish Independent reported.

"We don’t comment on rumor or speculation," a Ryanair spokeswoman said, declining to comment on the accuracy of the quotes. A serving Ryanair pilot told Reuters he had heard a recording of the meeting and the quotes were accurate.

People at the airline were "really pissed off," Bellew was quoted as saying, adding his biggest concern now was trying to get pilots to remain at the company after a lot of the airline's co-pilots handed in their resignations a couple of weeks ago.

Ryanair in September canceled 20,000 flights after it said it had a shortage of standby pilots after its rostering department mismanaged a rule change by the Irish regulator.

Resolving the operational problems that caused the cancellations was the top priority of Chief Executive Michael O'Leary and the company's board, Bellew said. "We won't let this happen again," he added.

Bellew, who returned to Ryanair on Dec 1 after two years at Malaysia Airlines, was quoted as saying staff had been "actively discouraged" from highlighting problems at the airline.

"Everywhere I turned, I could see that people were asking for small things to be done and they just weren't getting done," Bellew was quoted as saying. "Or, not only were they not getting done, they were getting told: 'Piss off; I don't want to know about this'."

Chief People Officer Eddie Wilson was quoted as saying at the same meeting that O'Leary had admitted mistakes had been made.

"He does recognize, and of course the board recognizes that, that we did take our eye off the ball ... The reason we're in the trouble we're in ... is that we grew too fast," Wilson was quoted as saying.

Ryanair is due to fly 129 million passengers in the year to March 2018, up from 90 million in the year to March 2015.