German airline Lufthansa said Sunday that its services were more or less back to normal after a four-day walkout by pilots, but unions warned of further disruptions, possibly over the Easter holidays.
A Lufthansa spokesman said short and medium haul flights were back to normal on Sunday, but a small number of long-haul flights were still cancelled.
However, a spokesman for the pilots' union Vereinigung Cockpit warned of further action in the coming weeks as there was no sign of an agreement.
"There's been no movement so far," the spokesman said, refusing to rule out further stoppages at just 24 hours' notice, and possibly over the Easter break in April.
Management and unions are embroiled in a bitter dispute over pilots' early retirement provisions.
Originally, Vereinigung Cockpit had called for a 24-hour walkout last Wednesday, but subsequently extended the industrial action over four days.
Short and medium haul services were cancelled on Wednesday and Friday, and there were no long haul and cargo flights on Thursday and Saturday.
In all, around 220,000 passengers were hit by the four-day walkout, Lufthansa said.
It has been the 12th and longest stoppage since the pilots began their industrial action last April.
The dispute hinges on Lufthansa's plans to scrap an arrangement under which pilots can retire at 55 and receive up to 60 percent of their pay until they reach the statutory retirement age of 65.
Pilots are also concerned about Lufthansa's bid to further develop its low-cost activities as it faces growing competition.
However, the head of the shareholder lobby group DSW told a Sunday newspaper that union representatives should no longer be allowed to sit on Lufthansa's supervisory board.
"Shareholders have had enough," Marc Tuengler told Bild am Sonntag.