Numerous flights from Geneva, Zurich and Basel have been cancelled.
A strike in France, which starts on the evening of 9 October and runs until the evening of the 10th, will affect flights in and out of France, along with flights through French air space.
Easyjet warns some flights will be delayed while others will be cancelled.
Air France has announced it hopes to fly 75% of its short and medium haul flights but that delays and cancelations cannot be ruled out. At the same time, the airline posted a long list of cancelled flights.
Swiss lists 10 cancelled flights, all in and out of Paris.
According to French newspaper Le Figaro, the strike will reduce the number of flights by 30%. France’s unions have called the strike in protest against a freeze on automatic pay rises, layoffs, and a plan to roll out a one-day stand down period on the payment of sick pay.