Geneva Airport reported some of its staff planned to strike on Friday, causing flight delays and cancellations at the start of the summer tourism season.

“The strike announced by the public service trade union is regrettable because it is taking place on the first day of vacation departures, including those of employees,” the airport stated in a statement Thursday.

“Flight delays and cancellations are very likely.”

In a separate notice on its website, the airport called on passengers to arrive two and a half hours before their flights.

The airport said the strike was called after its board of directors approved a salary policy that freezes pay increases for some employees.

Geneva Airport is a hub for diplomats and officials travelling to the United Nations.