Delays and cancellations are expected when workers at Budapest's Ferihegy International Airport begin an indefinite strike at 6 am (0500 GMT) on Wednesday, dpa reported.
A spokesman for Budapest Airport told the state news agency MTI that there are 250 flights scheduled in and out of Budapest Wednesday.
Krisztina Nemeth, a spokeswoman for the Hungarian national airline Malev said she could not say how many flights will be affected, as Malev had not yet been officially informed of the strike.
The strike was announced after unions and management failed to come to an agreement in last-minute talks on Tuesday. Negotiations over terms and conditions have been dragging on for five months.