The woman, who had no checked baggage, was taken into custody by federal authorities, the Bangor Daily News reported. She was described as a French citizen born in Cameroon.
US Airways Flight 787 was traveling from Paris to Charlotte, N.C., with 179 passengers and a crew of nine when it was diverted to Bangor International Airport about noon, airport Interim Director Tony Caruso said.
The North American Aerospace Defense Command said two F-15 fighters escorted the plane.
Sen. Susan Collins, R-Maine, said she had been told by Transportation Security Administrator John Pistole the woman had passed a note to a flight attendant saying she was carrying a surgically implanted device. Two doctors aboard the plane examined her but found no evidence of recent scars, Collins told the Daily News.
Caruso said the plane was deemed safe about 2 p.m. and the passengers taken to a secure area.
"The passengers were relatively calm given the situation," Caruso told the Daily News.
Boston FBI spokesman Greg Comcowich said no one ever was in any danger on the plane.