The Commission has extended a deadline for examining Lufthansa's planned acquisition of Air Berlin units Niki and LGW to Dec. 21. It is concerned about Lufthansa's potential dominance in Germany and is seeking feedback on concessions put forward by the airline.

"We believe that the regulatory authorities should ensure that sufficient slots from the Air Berlin failure should be made available to Ryanair," the Irish carrier's chief commercial officer, David O'Brien, told Reuters.

A source familiar with the process said on Wednesday that Lufthansa's current concessions included divesting some Niki slots in Germany but keeping those in congested Munich and Berlin Tegel. While the German carrier plans to give up some Niki slots in Duesseldorf, LGW's portfolio also includes peak-time slots there.

"Ryanair is interested in access to slots -- not slots contrived to deliver an inefficient operation, but sufficient slots to run a modern, efficient low-cost operation out of, for example, Munich, Frankfurt, Duesseldorf and Berlin Tegel," O'Brien said.

Ryanair did not enter the bidding for Air Berlin assets, but rival easyJet is starting new German domestic routes after buying Air Berlin operations at Berlin Tegel.

O'Brien said that Ryanair, which is currently taking delivery of 40 to 50 planes a year, could station 10 aircraft at those four German airports within a year and would look at domestic routes, though international destinations are more likely.

Ryanair has nine aircraft stationed in Berlin Schoenefeld and plans for 10 in Frankfurt next summer.

However, self-inflicted rostering problems have forced Ryanair to scale back growth plans this winter, including the scrapping of its sole German domestic route between Cologne and Berlin and a reduction in planes stationed at Frankfurt to six from seven.

O'Brien said the Cologne-Berlin route would be reinstated next summer.

He also repeated Ryanair's view that the Air Berlin sale process was designed to minimise competition for Lufthansa.

"These entities should simply be allowed to disappear and the slots should go back into the pool and more efficient airlines should organically grow and deliver consumers what they want," he said when asked if Ryanair would bid for Niki should the sale to Lufthansa not be approved.

British Airways has dropped its renewed interest in Niki, a source familiar with the matter said on Thursday.

(Reporting by Victoria Bryan; Editing by David Goodman)

By Victoria Bryan