Security is being stepped up at Zurich and Geneva airports after an attempted act of terrorism on a flight from Amsterdam to Detroit in the United States.
Officials say a Nigerian 23-year-old man, suspected of links to terrorist group al-Qaida, was trying to ignite an explosive device as the Northwest Airlines Flight began its descent to Detroit.
As a result of the incident, US authorities have asked for increased surveillance around the globe.
Swiss International Airlines is warning passengers on flights to the US to prepare well in advance. They should arrive at the airports as early as possible and take as little hand luggage as possible.
The new directives will come into force on Sunday and last for at least four days.
After having passed customs authorities, passengers to the US will be subject to further identity and hand luggage controls, a Swiss spokeswoman said.
Swiss has up to eight flights daily to the US from Zurich and Geneva.
swissinfo.ch and agencies