Ryanair (FR, Dublin International) would consider opening up services to Paris CDG should operator Aéroports de Paris (ADP) reduce its fees. Ryanair Chief Commercial Officer David O'Brien told a press conference in Paris last week that the launch of any service would compliment, rather than compete, with its existing Paris Beauvais operations.

"Serving Paris Charles de Gaulle? Why not. Paris Orly airport is full due to constraints in terms of slots, but not Charles de Gaulle," La Tribune quoted him as saying. "But, we have no immediate plans to serve Roissy, an airport that has the drawback of being expensive. At the moment, growth in Germany is still the priority for us."

Though its operations have historically focussed on secondary airports, the Irish budget carrier has begun to switch its attention to Europe's larger primary hubs as it moves to capture the lucrative business-traveller market. As it stands, primary airports that could see a Ryanair presence in the near future include Amsterdam Schiphol, Munich, and Milan Malpensa.

In an interview with the Irish Independent last year, O'Brien said Ryanair's priority for 2015 would be to give business travellers improved access access to capital cities by increasing both its network and frequencies.

Paris CDG, along with Frankfurt International and London Heathrow, have, in the past, not been considered suitable given their costly landing fees as well as excessive aircraft turnaround times.

Ryanair's arrival at Europe's main hubs is likely to give legacy carriers such as Lufthansa (LH, Frankfurt International), KLM Royal Dutch Airlines (KL, Amsterdam Schiphol), Air France (AF, Paris CDG), British Airways (BA, London Heathrow), and Iberia (IB, Madrid Barajas) more cause for concern given its already hefty impact on their share of the European domestic and regional markets.

Given the LCC dominance of Europe's skies, CEO Michael O'Leary says he sees a future in which Ryanair, along with easyJet and Wizz Air (W6, Budapest), all act as feeder carriers to legacy airlines for international routes.

"We could be doing contract flying for high-fare carriers and feeding high-fare carrier hubs, but I would see that operating on the basis that the high-fare, long-haul carrier would simply want access to our low-cost seats," he said. "Easyjet in London Gatwick could be feeding British Airways, Ryanair could be feeding Lufthansa or Air France. It's not something that I'd see them looking at in the short-term, but I think it's an inevitability over the medium term."