One flight, from Washington DC to Paris, was diverted to Halifax, Nova Scotia, while the other, from Los Angeles to the French capital, was diverted to Salt Lake City.
Two Air France flights en route to Paris from the United States were diverted on Tuesday because of security issues, and passengers and crew were safely removed, the Federal Aviation Administration said.
An Airbus A-380 that departed from Los Angeles landed in Salt Lake City, where passengers and crew were being taken off the plane and escorted into the terminal, an FAA spokesman said.
A separate flight that left Dulles International Airport outside Washington was diverted to Halifax International Airport in Nova Scotia, also because of an unspecified security concern, and passengers and crew had disembarked, the FAA said.
Halifax airport spokesman Peter Spurway said the Air France Boeing 777 jet was diverted to Halifax at 10:15 p.m. eastern time and was currently sitting at the end of the airport's main runway.
"It's an RCMP matter," Spurway said referring to the Royal Canadian Mounted Police. "The passengers are being deplaned at this point and being transferred to a secure area of the terminal building because they're international passengers."
CNN, citing a US government official, reported that Flight 65, the flight which originated in Los Angeles, was diverted after a bomb threat was called in from the ground. The official did not know if anyone was arrested in connection with that incident.
"Several law enforcement agencies are working in concert, following established protocol, to determine the nature of the threats which caused the aircraft to divert," FBI Special Agent Todd Palmer, of the agency's Salt Lake City division, told the network.
Security officials have been on high alert since last week's deadly attacks in Paris, claimed by Islamic State militants, killed 132 people.
France and Russia on Wednesday agreed to coordinate their military and security services in an unusual alliance against Islamic State militants in Syria on Wednesday after a devastating attack on Paris and the bombing of a Russian plane earlier.
Warplanes from both countries unleashed bombs on the IS stronghold of Raqa as Paris and Moscow vowed merciless retaliation for attacks that have galvanised international resolve to destroy the jihadists and end the nearly five-year Syrian war.
"It's necessary to establish direct contact with the French and work with them as allies," Russian President Vladimir Putin told his military top brass as France prepared to send its flagship aircraft carrier to the eastern Mediterranean, where the Russian navy is deployed.
Hollande will hold talks on strengthening cooperation against IS with Putin in Moscow on November 26, two days after seeing US President Barack Obama in Washington.
Earlier, police in France racked up arrests and seized weapons as they scoured the country for clues after a wave of coordinated attacks by gunmen and suicide bombers on Friday night.
Only 117 of the victims have been identified and 221 people are still in hospital.
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