Thursday's suspected terrorist threat in Britain continues to cause disruption to some flights to and from Switzerland's main airports.
The situation at London's Heathrow airport, hardest hit by an alleged bomb plot, had eased by the end of Thursday. But changes to flight schedules are likely to continue.
British Airways on Friday cancelled two flights from Zurich airport and three from Geneva.
Only one BA flight has left Geneva airport so far for Heathrow. Normally eight leave daily for the London airport.
"This is all the more problematic because around 50 per cent of their passengers are on connecting flights for Canada or the United States," said Geneva airport spokesman Philippe Roy.
All eight easyJet flights to and from London airports - Gatwick, Stansted and Luton - have been cancelled.
At Zurich airport, Swiss International Air Lines' flights to Britain are running, but with delays of up to half an hour. The carrier is still flying to London City from Geneva.
One BA flight has been cancelled at Basel airport and the three easyJet flights are taking place.
Geneva airport's Roy said it was still difficult to know when the situation would return back to normal, especially as Friday and the weekend are busy periods.
He told the Swiss News Agency that a return to normality was expected by the beginning of next week.
Passengers were turned away from Zurich, Basel and Geneva airports on Thursday as flights to British destinations were delayed or cancelled.
Swiss, which cancelled five flights between Zurich and Heathrow, reported that 660 passengers had been hit by the scare.
British Airways cancelled all its flights to and from Heathrow, affecting five flights from Zurich.
At Geneva, BA cut about 15 flights but Swiss had managed to resume flights to Heathrow by late afternoon, according to Roy.
Five easyJet flights either to or from Luton and Gatwick were also cancelled.
But Swiss could fly in and out of London City airport.
The Swiss federal authorities said they were monitoring the situation but issued no specific security advice.
The dramatic development in Britain followed the discovery of a possible terrorist plan to blow up planes flying from Britain to the United States by smuggling bombs on board in hand luggage.
After the announcement that British authorities had arrested 21 people (later 24) and tightened security, airports in Switzerland also adapted to the situation.
Airlines introduced new security measures on direct flights to Britain and the United States. Hand luggage, in particular, is still subject to the new regulations.
Swiss informed its passengers that hand luggage was forbidden on flights from Britain. Spokeswoman Elle Steinbrecher said that only wallets, passports, urgent medicines and baby milk were being allowed.
The cancellations and delays caused a few headaches for travel agents, with many passengers asking for transfers on other flights or other solutions.
After Thursday's terror alert, passengers flying to London or the United States were advised to check in two hours before flight departure and check for information on the internet site of the airline company concerned.
swissinfo with agencies
Basel airport operates nine flights a day to London, three of them to Heathrow.
Zurich airport operates 12 flights a day to Heathrow and also flies to Gatwick, London City and Luton airports in the area. British Airways has cancelled all its six flights from Zurich to Heathrow on Thursday.
Geneva airport operates eight daily flights to Heathrow, and also services Gatwick, Stansted, London City and Luton airports.