An unexpected warning strike by the Verdi union brought Hamburg Airport to a standstill on Sunday and had a massive impact on national and international air traffic. The industrial action was originally only planned to begin on Monday, but with only 30 minutes' notice, the strike began on Sunday. While hundreds of flights were already cancelled that day, a total of around 3.400 flights are affected on Monday, meaning that around 510.000 passengers will not be able to travel as scheduled. Sudden start of strike causes chaos The decision to bring the strike forward at short notice caught not only travelers off guard, but also the airport companies. At Hamburg Airport, 144 arrivals and 139 departures were planned for Sunday, but only ten planes were able to take off. The remaining flights were cancelled without replacement, which led to significant restrictions in air traffic. International destinations such as Vienna, Salzburg, Graz and Innsbruck were also affected. A spokesman for the airport sharply criticized the measure: "We are appalled at how ruthlessly the union is acting. Ultimately, it is primarily the people who depend on their travel that are affected." Significant disruptions are expected on Monday. The airport company advised all travelers to contact the respective airlines directly to discuss alternative travel plans. Union defends industrial action Ver.di justified the action as a necessary measure to enforce the collective bargaining demands. Union secretary Lars Stubbe stressed that the impact on passengers was regrettable, but that economic pressure had to be put in place in a targeted manner. According to Stubbe, employers would react to long-announced strikes by taking countermeasures such as using strikebreakers. A sudden strike without much advance notice would be