The cabin crew and ground staff have reportedly issued a list of 34 demands including "predictable working hours".
The pilots will engage in strike action next week for a period of 24 hours, commencing at 1am on Thursday 12 July. Other countries may join the action, he added.
The dispute is over management's approach to the transferring of pilots between it's African and European bases.
Ryanair, which flies in 37 countries and carried 130 million passengers last year, averted widespread strikes before Christmas by deciding to recognise trade unions for the first time in its 32-year history, but has since struggled to reach agreement on terms with a number of them.
"If Ryanair fails to respond promptly and appropriately then it risks industrial action over the summer", he said.
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Pompeo denied that the talks went poorly, telling pool reporters that progress was made "in every element of our discussions". There is a wide gap in views between Washington and Pyongyang over the scope and compensation of the repatriation.
A spokesman for Ialpa said: "Our member pilots directly employed by Ryanair complain that there is no transparent system for the determination of important matters including voluntary/involuntary base transfer/allocation, command upgrade, allocation of annual leave and promotion".
Cabin crew sources said unions may name dates for strikes in Italy, Belgium, Spain and Portugal at a meeting in Brussels today.
The airline said yesterday: "Ryanair will communicate next Tuesday by email and SMS text with all customers travelling from Ireland next Thursday if this unnecessary strike goes ahead". Ryanair said the cancellations compare with just 41 in June past year.
Covering areas like pay, rostering, contracts and sickness, the eight-point charter includes some demands that would be taken for granted by many cabin crew at other airlines.
The industrial action will affect hundreds of flights in and out of Ryanair's primary base at Dublin as well as Cork and Shannon.
It follows cancellations of more than 1,100 flights also in May.