The authorities have decided to extend a ban for commercial air travel as a plume of volcanic ash from Iceland continues to hang over central and northern Europe.
The Federal Civil Aviation Office said Swiss airspace would remain closed until Sunday 2pm for aircraft flying at an altitude below 6,000 metres.
Thousands of air travellers were stranded as flights from and to Switzerland were cancelled for a second day and virtually all of Europe's major airports remain closed.
Swiss International Airlines announced its fleet would remain grounded on Sunday.
President Doris Leuthard had to call off her visit to Poland to attend the funeral of the Polish president, Lech Kaczynski.
A weather expert said the cloud of volcanic ash had hardly moved all day Saturday and the meteorological conditions were set to remain unchanged for the near future.
The shutdown of commercial air travel led to overcrowded trains in Switzerland despite extra services laid on by the Federal Railways.
Car rentals, taxis and hotels also recorded massive bookings.
The disruption has affected millions of people since the volcano under the Eyjafjallajokull glacier in Iceland began erupting again on Wednesday.
It is costing airlines more than $200 million (SFr213 million) a day, the air industry body IATA estimated.
swissinfo.ch with agencies