http://www.anna.aero/2011/02/02/aegean-olympic-merger-denied...

A part from Air France almost every country's dominating carrier has around 60% or less. And this is for domestic travel only, which is not very extensive due to the smaller size of European countries and the vast reach of high-speed rail.

If you look at international travel the main carriers have massive amount of competition from low-cost carriers as well as airlines from other European countries:

http://www.anna.aero/wp-content/uploads/2011/03/air-france-3...