A Ryanair airplane taxis in Weeze, Germany, September 12, 2018. REUTERS/Wolfgang Rattay

ROME (Reuters) - Unions representing three of Ryanair's RYA.I Italy-based cabin crews said on Thursday they had reached an agreement in principle for a three-year collective labor agreement, according to a statement.

Italian cabin crews represented by the Uiltrasporti union have threatened to strike later this month to pressure Europe’s biggest budget airline to accept local contracts.

Fit Cisl, Anpac and Anpav unions signed Thursday’s agreement, but Uiltrasporti was not mentioned.