A woman was removed from a flight from Paris to the US after wires were seen coming from her jacket.
Passengers were questioned on arrival in Cincinnati
She was in transit from the Jordanian capital, Amman, when she was taken off a Delta flight to Cincinnati.
It later transpired that she was "a young lady with an unusual jacket", with wires and a battery used to heat it, a US official said.
The woman, a French national, was cleared to travel on a later flight to Cincinnati.
When Delta flight 43 arrived at Cincinnati/Northern Kentucky an hour late at 1554EST (2054GMT), it was subject to "additional screening", even though the woman was not on board.
The plane was held in an area away from the terminal building, passengers were questioned and all baggage was checked, in what one US official called an "abundance of caution".
There were 184 passengers and 12 crew on board.
The woman first came to the attention of security officials at Charles de Gaulle airport when her leather motorcycle jacket aroused suspicion.
The French authorities then told US security officials that the woman had been taken off the flight.
She was questioned briefly and her baggage was thoroughly searched. She had no police record.
Delta said that it was "co-operating fully with federal security agencies" over the alert.
There were conflicting reports that the Boeing 767 was escorted by fighter jets as it entered US air space.
One man waiting for the flight to arrive at Cincinnati said his son on board the plane had reported seeing jet fighters escorting for the plane for about 40 minutes over the Atlantic Ocean, and then pulling away when the plane crossed over New York state.
British Airways has cancelled two flights from London to Washington in the past week, due to security fears, and three Air France flights from Paris to Los Angeles were cancelled over Christmas.