Authorities say 12 passengers on two flights from Europe were evaluated for sore throats and coughs upon arrival at Philadelphia International Airport, but none were considered severely ill.
A federal Customs and Border Protection spokesman says the sick passengers had been attending the hajj in Mecca, Saudi Arabia.
Officials say passengers from the two flights on Thursday afternoon who weren't sick continued on with their travel plans.
The group of illnesses comes a day after 10 people were hospitalized and tested positive for influenza after arriving by plane in New York from Dubai.
The Centers for Disease Control and Prevention says none of the 12 passengers coming to Philadelphia on American Airlines flights from Paris and Munich exhibited fevers.
An American Airlines spokeswoman says the plane wasn't quarantined.