Berlin, April 25 : Operations at two major German airports were severely disrupted by walkouts on Monday, following nationwide strikes by public sector employees last week. On Monday, strikes hit the airports in the capital Berlin, as well as in Hamburg which was already affected on Thursday and Friday. "Because unions and companies in the security industry cannot reach an agreement, tens of thousands of passengers cannot be checked, and hundreds of flights have to be grounded," Ralph Beisel, CEO of the German Airports Association (ADV), told Xinhua news agency on Monday. At Hamburg Airport, walkouts by 300 employees of a ground service provider caused the cancelation of almost a third of departures. From Berlin Brandenburg Airport, there will be no departures at all on Monday, as the airport's entire aviation security staff is on strike. After months of negotiations, and numerous strikes in transport, childcare, and other sectors in Germany, a major breakthrough in collective bargaining negotiations was achieved over the weekend. A total of 2.5 million public sector employees in Europe's largest economy will receive a one-time payment of 3,000 euros ($3,300) to compensate for high inflation, as well as a wage increase of 5.5 per cent -- or at least 340 euros per month. "With our decision to enter into this compromise, we have gone to the pain threshold," said Frank Werneke, chairman of the United Services Union (Verdi), on Saturday. Until the agreement was reached, the union was demanding a wage increase of 10.5 per cent. Despite the lower overall wage settlement, the rise will add up to more than 11 per cent for most employees, Werneke stressed. "This is a sustainable increase in income, which is considerable." Despite the agreement for Germany's public sector, an end to the strikes is not in sight. The energy industry is still hit by work stoppages, while a rail union has already announced plans to bring traffic to a standstill again unless employers improve their offer. (1 euro $1.10) /IANS