A second day of work stoppages at Budapest's Ferihegy International Airport led to further chaos for passengers on Thursday, dpa reported.
Representatives of striking airport staff spurned requests from management to call off their strike and return to the negotiating table.
Instead, union leaders on Thursday evening escalated the dispute with an open letter to Herbert Luetkestratkoetter, the chairman of the executive board of Hochtieff, the German owner of Budapest airport, local news agency MTI reported.
Despite long queues and a number of passengers having slept overnight at the airport, the local news agency MTI reported relative calm at the terminal. "The situation has improved compared to yesterday morning," said Domokos Szollar, spokesman for airport operator Budapest Airport.
In the afternoon, however, familiar scenes of airport chaos were played out. The daily Nepszabadsag reported queues of several thousand frustrated passengers when a bottleneck formed at a passport control center manned by a single worker.
On Wednesday, the first day of the strike, the airport came to a standstill at 7 am (0600 GMT) when security staff walked out, effectively cutting off the flow of passengers to the departure gates. Fifty of 250 scheduled flights in and out of Budapest had to be cancelled.
By late afternoon on Thursday, 30 out of 264 flights on the day's schedule had been cancelled, mostly by the Hungarian national airline Malev, which had already decided on the cancellations the day before.
Management and unions were still not talking.
"The unions will go ahead with the strike and reject the employer's ultimatum that the resumption of negotiations is conditional on our calling off the strike," said Zoltan Kovacs, strike leader and head of one of the two main unions representing workers at the airport, on Thursday morning.
Budapest Airport management responded by saying the company would not give in to "blackmail," and insisted it will carry on with restructuring, which it says will serve to protect jobs.
The National Association of Workers' Councils and the LIGA federation of unions pitched in with criticism of airport management on Thursday afternoon.
In a statement, the former expressed particular outrage at Budapest Airport's references to the financial crisis as justification for its restructuring.
LIGA accused Budapest Airport of having committed a "grave and unacceptable" error by using the term "blackmail" and refusing to negotiate with the striking workers on their own terms.
An indefinite strike was called on Tuesday immediately after talks between management and airport workers' unions broke down.
Airport staff are unhappy with management proposals for changes to working conditions, and are demanding reassurances that there will be no redundancies before 2010.