Flights between Paris and Los Angeles were to resume Friday.
No arrests were made, and French authorities released seven men — one French, one American and several Algerians — after briefly questioning them late Wednesday, said an Interior Ministry spokesman. He said the investigation was all but on hold.
A French judicial official who spoke on condition of anonymity said that none of the passengers on the canceled flights, including those who were questioned at the airport, were known to intelligence authorities or had known links with Islamic extremist groups.
The people held for interrogation were chosen because their names appeared on a list provided by American authorities, the ministry spokesman said on condition of anonymity.
U.S. intelligence had the exact flight numbers and the names of suspected al Qaeda operatives who might be on the flights, reports CBS News National Security Correspondent David Martin. The manifest for at least one of the flights had one or more names similar to the names of the suspected terrorists.
The French judicial official said that there was not enough evidence of a possible terrorist attack and that, as a result, a formal investigation had not been launched.
The official also said the name of a Tunisian national with a pilot's license had appeared on the American list of suspicious people who may attempt to board a flight. But French intelligence officials determined that the man was in Tunisia and had no plans to leave the North African country.
The official added that the Tunisian had no criminal record and did not belong to any Islamic radical groups.
Intelligence warnings of possible terrorist plots to use aircraft against American targets prompted the cancellation of six Air France flights between Los Angeles and Paris on Wednesday and triggered intense security talks between U.S. officials and their foreign counterparts.
Three of the canceled flights were headed to Los Angeles and three more were returning to Paris.
The U.S. also has intelligence that airline attacks could occur over New Year's, but the most immediate threat was the flights from Paris to Los Angeles over Christmas, reports Martin, and that threat, if it was real, has been avoided.
Security was tighter at LAX airport Christmas Day, reports Angela Chee of CBS station KCAL-TV, including pre-screening at the airport, random search of cars arriving at the airport, and a ban on curbside drop-off. "Only limos, buses and taxis are allowed near the curb," said Che3.