The prosecutor's office said Umar Farouk Abdulmutallab did not have an accomplice at Schiphol Airport in Amsterdam, as some other passengers on the flight had alleged.
Abdulmutallab, 23, the son of a prominent banker, flew from Lagos to Amsterdam on a KLM flight, arriving on Christmas Day. Prosecutors said the seats from that plane are still being examined for traces of explosives.
In Amsterdam, Abdulmutallab went through a profile interview and a security check before waiting at the gate for his flight.
He is charged with trying to blow up the flight, Northwest Flight 253, outside of Detroit with a highly explosive substance hidden in his underwear.
Some of the passengers on the plane had said they saw him accompanied at the gate in Amsterdam by an older, well-dressed Indian or Pakistani man. But the review of more than 200 hours of video showed no one with him, the officials said.
(Reporting by Ben Berkowitz; Editing by Jon Boyle)