Passengers travelling with Ryanair in Germany on Friday saw little disruption from a four-hour strike called by a pilots' union, with most flights leaving as scheduled, and only some delays.

Germany's powerful Cockpit union had asked Ryanair pilots to walk off the job from 5-9am (0400-0800 GMT) in a battle for recognition from the Irish no-frills carrier whose workers have been calling for better pay and conditions across Europe.

But the first-ever strike action by Ryanair pilots in the company's 32-year history appeared to have made little impact, with no cancellations reported.

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

Flights left mostly 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, at least one Ryanair flight to Copenhagen suffered from the strike action with passengers being told to expect a 10-hour delay.

The Cockpit union said it was pleased with the response to its strike call, which had forced Ryanair to scramble to bring in pilots from abroad.

"The strike participation has been absolutely satisfactory," union spokesman Markus Wahl told DPA.

The Irish carrier itself has urged passengers to head to airports despite the strike call, pledging to do its "upmost to minimise any disruptions".

Cockpit had on Thursday called for a "warning strike" 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.

Cockpit accused Ryanair of playing for time to avoid travel chaos during the busy Christmas period.

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

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 eased tensions but unions warned that strikes remained an option if the Dublin-based carrier was not serious about the discussions.

Ryanair was able to stave off year-end travel 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.