Ryanair pilots balloted by the Irish Air Line Pilots' Association have voted overwhelmingly to back strike action in their dispute over terms and conditions.
A 24-hour strike is planned on Thursday 12 July.
Pilot unions say they will notify the airline of further stoppages in due course and remain available for engagement.
The unions have claimed that Ryanair is not taking them or their demands seriously and that progress on improving pay and conditions for staff is too slow.
In a statement, Ryanair said it was disappointed by the strike notice, which the company described as unnecessary.
The airline said it had already forwarded draft proposals on recognition, base transfers, a seniority list for all Irish pilots and a new annual leave system based on seniority to IALPA's parent union, Fórsa.
Ryanair said it had invited Fórsa to meet to discuss these proposals on 18 separate occasions, but the union failed to reply or take up any of these invitations.
The airline said it will be in touch with customers affected by the strike by next Tuesday by email and text message.
Ryanair said Fórsa has been invited to a meeting next Wednesday morning to try to resolve the dispute.
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The Irish Travel Agents Association (ITAA) expressed concern over the Ryanair pilots vote for strike action.
CEO Pat Dawson said: "We're deeply disappointed to hear of the decision by pilots to strike next week as this will affect the peak of summer travel, causing major distress for holidaymakers. Any cancellations at this point will result in major consequences for travellers with booked accommodation and connecting travel plans completely disrupted, leading to additional costs to customers."
Mr Dawson called on Ryanair and its pilots to resolve their internal issues and prevent the proposed strike action.
He said the ITAA is advising all those planning to travel with Ryanair to contact their travel agent for further advice.
Two-day summit of Ryanair cabin crew
The International Transport Workers Federation has organised a two-day summit of Ryanair cabin crew from across Europe in Dublin under the banner of Cabin Crew United.
It too warns of potential industrial action if its concerns are not addressed.
Ryanair said that air traffic control strikes left more than 210,000 passengers facing flight cancellations last month.
It said more than 1,100 flights were cancelled for the second month running due to air traffic control strikes over four weekends in June, as well as staff shortages in the UK, Germany and France.
This compared with just 41 cancellations in June last year and the airline repeated its call for action from Europe to help tackle disruption from the strikes.
Air traffic control strikes are costly for airlines and hugely disruptive for passengers, especially in France, as many UK flights need to use the country's air space or fly longer routes to avoid it.
But the action has become a regular headache for the industry in recent years, with 2017 said to be a record for strikes, with 41 days affected.
Despite the strike action, Ryanair said it still flew 7% more passengers last month, at 12.6 million.
Its load factor - a measure of how well airlines fill their planes - remained unchanged at 96%.
Additional Reporting PA