The Defence Department has been forced to issue a statement explaining why there are US Air Force helicopters in the skies.
Three Blackhawk and three Chinook helicopters are in the country, from their home bases in Germany.
The Defence Department says the Swiss Air Force and the US Army are conducting joint exercises at the Payerne airbase.
It says the aim of the exercises are to ‘increase efficiency and operational readiness’.
They will last all week.