Heavy snowfall led to the temporary closure of Geneva airport on Friday morning, with around 30 flights cancelled.
The airport tarmac reopened at 9.30am, but delays are to be expected all day.
Geneva airport staff had to clear around 20 centimetres of snow which fell during the night, a spokesman said.
Zurich airport remains open, but is also badly affected with around 30 flight cancellations and delays of about half an hour.
Less snow is expected to fall later in the day.
It is the second time this month Geneva airport has had to close due to snow.
On December 1, around 200 stranded air passengers had to spend the night in emergency shelters, with a further 100 sleeping in the airport after buses and taxis could not serve the airport.
swissinfo.ch and agencies