Dates for walkouts by Ryanair cabin crew across four countries have been timed to hit the airline on some of the busiest days of the summer.

Cabin crew and ground staff in Italy, Belgium, Portugal and Spain plan to walk out on July 25 and 26 after issuing a list of demands in a “crew charter” this week.

Europe’s largest low-cost carrier dismissed the demands as “pointless” and said crew already enjoy good working conditions.

Details of the pan-European walkout – in Italy on July 25 and in Belgium, Portugal and Spain on July 25-26 – came ahead of about 100 Ryanair pilots based in Ireland planning to strike next Thursday.

The International Transport Workers’ Federation, an umbrella body assisting Ryanair crew unions in multiple countries, warned that the airline “can expect further strike action over the summer if it continues to ignore the legitimate demands of its workers”.

An ITF spokesman claimed Ryanair has failed to take seriously issues raised at a cabin crew summit in Dublin.

“Ryanair workers are frustrated by the lack of progress since the company announced that it would recognise unions in December 2017. Since then, only a couple of recognition agreements have been signed and there have been no concrete improvements in pay and working conditions,” the spokesman said.

“In dismissing the Ryanair crew charter, the company has further weakened its credibility with workers and their unions.”

The airline described net week’s threatened action by pilots as “unnecessary” and called for FORSA, the union representing them in Ireland, to meet.

“Should you fail/refuse to do so ten sadly thousands of customer journeys next Thursday will be unnecessarily disrupted by FORSA when many other pilot and cabin crew unions have already met with us and negotiated/agreed to positive and practical solutions to Ryanair pilot concerns,” chief people officer Eddie Wilson said in a letter.