Airports are deserted across France as air traffic controllers strike in protest against a single-sky plan for Europe.
Less than 10% of flights operated during the first few hours of the industrial action, confirms the US Civil Aviation Authority.
Disruption and delays have spread across Europe as Italian, Portuguese, Greek and Hungarian controllers joined the French protest. The "single-sky" plan is aimed at reducing congestion and delays.
EU transport ministers met in Luxembourg on Monday to discuss the scheme, which would bring all air traffic controllers under the same supervision so airlines can fly routes that are not defined by European borders.
But trade unions fear it will lead to the privatisation of air traffic control services, job losses and reduced air safety.
A similar strike by French workers last year caused massive disruptions across Europe with the cancellation of hundreds of flights.
The German construction workers union extended its strike campaign across the country, on the third day of a dispute that economists say could further damage an already battered industry.
The union is seeking a 4.5% pay rise and equalisation of wages in poorer east Germany with those in the west.
Officials say the last offer made by employers is more than some firms can afford.