The French civil aviation authority (DGAC) said as many as one in two flights would be scrapped on Thursday, the second day of the strike.
Budget airline easyJet (>> easyJet plc) said it was cancelling 118 flights to and from France on April 8 and apologized to passengers for a strike "outside of our control".
Low-cost carrier Ryanair
The state-employed air traffic controllers are threatening further two-day stoppages later in April and at the start of May -- when school breaks and public holidays boost vacation traffic -- over what they say is management refusal to take their demands seriously.
In a blog post, the SNCTA trade union denounced plans to raised the age at which controllers are entitled to retire and highlighted other complaints, including declining staff numbers at a time of increasing national and European regulation.
Air France (>> Air France-KLM) had advised passengers on Tuesday that 40 percent of medium-haul flights would be canceled, with as many as two thirds of short-haul flights scrapped at Paris Orly and other French airports.
(Reporting By Brian Love; Editing by Larry King)