The budget airline has said that staff were not aware of the racist comments until after the flight and that they dealt with what they believed was an argument according to protocol.
In the statement Ryanair said that they reported the incident to both Essex Police and Barcelona Police.
The statement said;
"Ryanair's Spanish cabin crew were aware of an argument between these two passengers during the boarding process, but were not aware of, as they were not present when, racist comments that were made by the male passenger towards the female passenger.
"While these events were videoed by another passenger on a mobile phone, this video was not shown to cabin crew until after landing in London Stansted. Ryanair did not become aware of the contents of the video until late on Saturday evening when it gained widespread coverage on social media.
"As the cabin crew believed they were dealing with an argument between two passengers, they followed company procedure, to defuse the argument, and separate the passengers by offering to move one to alternative seating. In this case, the female passenger was moved at her request. After moving the female passenger, both passengers were asked if they were "OK", and both confirmed that they were."
The airline spokesperson went on to say that they wrote to the female passenger to apologise on Sunday morning.
Ryanair's head of communications, Robin Kiely, said: "We again extend our very sincere apologies to this passenger for the regrettable and unacceptable remarks that were made to her by an adjacent passenger, and we believe that, by reporting this matter immediately to Essex Police, and by apologising in writing to this customer early on Sunday morning, Ryanair treated it with the urgency and seriousness it warranted."
This comes as the man who launched the racist tirade has appeared on television to claim he is not a racist.
David Mesher told ITV's Good Morning Britain that the dispute with Delsie Gayle began over getting to his seat.
He said: "I probably lost my temper a bit and ordered her to get up."
Asked if he regrets his language, he replied: "Absolutely. I'm not a racist person by any means and it's just a fit of temper at the time, I think.
"I apologise for all the distress you've had there and since."
Both Ms Gayle and her daughter Carol Gayle told the TV show that they rejected his apology.
When asked if she accepts the apology, Delsie Gayle said: “I don’t think so. You must forget and forgive but it’s going to take a long time for me to get over what he has done to me.”
Her daughter added: “He says he wasn’t racist, he wouldn’t be saying words like that if he wasn’t racist.
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