Passengers travelling with Ryanair in Germany on Friday saw little disruption from a short strike called by a pilots' union, with the no-frills airline praising crew for "largely ignoring" the unprecedented walkout.

Germany's powerful Cockpit union (VC) had asked Ryanair pilots to walk off the job from 5-9am (0400-0800 GMT) in a battle for recognition from the Irish carrier whose workers have been calling for better pay and conditions across Europe.

But the impact of the first-ever strike action by Ryanair pilots in the company's 32-year history was limited, causing just some delays and no cancellations.

Ryanair said nine of the 36 flights scheduled to depart within the strike window were delayed by the actions of "a small number of pilots".

"We are grateful to all of our Ryanair pilots for putting our customers first and largely ignoring this VC strike," it said in a statement.

"We apologise sincerely to our customers for any inconvenience suffered as a result of this unjustified and unnecessary strike," it added.

At Germany's busiest travel hub, Frankfurt airport, all six scheduled Ryanair flights left as planned, according to DPA news agency.

Most flights left as planned at Berlin-Schoenefeld airport as well, where seven departures were on the board. The 6:40 am flight to Italy's Bergamo however was delayed by five hours.

At the Cologne/Bonn airport in western Germany, passengers for a Ryanair flight to Copenhagen were told to expect a 10-hour delay.

The Cockpit union nevertheless said it was satisfied with the response to its strike call, which had affected one in four Ryanair flights and forced the company to scramble to bring in pilots from abroad.

"The goal today was not to cause as much flight chaos as possible. Ultimately, people need to make it to their destinations this close to Christmas," union president Ilja Schulz told public broadcaster ZDF.

"The goal was simply to show Ryanair that the pilots we called on to strike are willing to fight for better working conditions now."

- Historic U-turn -

Ryanair last week took the unprecedented step of offering to finally recognise unions after crew in Germany, Ireland, Britain, Italy, Spain and Portugal threatened walkouts in long-running rows over pay and conditions.

The move initially prompted unions to suspend their strike plans, averting the threat of major upheaval over the busy holiday period.

But Cockpit on Thursday decided to launch a "warning strike" after all after a first round of talks with Ryanair broke down this week.

The union said the discussions were cancelled after the carrier objected to two of the five union members present.

It accused Ryanair of playing for time to avoid travel mayhem over the Christmas and New Year period and of trying to dictate the conditions for the talks.

But the airline hit back, saying it would not negotiate with non-Ryanair pilots.

The Dublin-based budget airline was however able to stave off year-end flight chaos on home soil after clinching a deal with Ireland's Impact union on Thursday.

The union there said the danger of industrial action had "receded for the present" after Ryanair agreed to formally recognise Impact as the representative for the airline's pilots.

In Italy, the union Anpac said it planned to meet with Ryanair representatives in Rome in January.

Ryanair's decision to move towards trade union recognition marks a historic turning point, given that pugnacious boss Michael O'Leary -- in charge since 1994 -- had vehemently opposed any union representation for staff.

But he came under increasing pressure after the airline was forced to cancel 20,000 flights through to March because of botched holiday scheduling.

The fiasco triggered pilots' demands for better working conditions and representation, with some departing for other carriers.

Ryanair, Europe's second-largest airline by passenger numbers, has set itself the goal of transporting 200 million passengers annually by 2024.

Despite the recent troubles, it still expects to deliver annual profits after tax of 1.40 billion-1.45 billion euros ($1.65 billion-1.71 billion).