A strike by French air traffic controllers entered its second day on Friday, leaving many passengers stranded at the start of Europe's peak travel season.
Civil aviation agency DGAC told airlines to cancel 40% of flights at the three main Paris airports on Friday because of the strike, which the air traffic controllers say is over staff shortages and ageing equipment.
Up to half of flights at France's other airports, mostly in the south, were also affected, DGAC added.
