Investigators believe it is in response to the 10th anniversary of the Sept. 11 attacks on the U.S.
Officials said the threat is only directed toward New York and Washington D.C. Both cities are increasing their security efforts.
The Department of Homeland Security said the threat is "specific, credible but unconfirmed."
New York's mayor said all events for this weekend's 9/11 anniversary will go on as planned.
For weeks now, federal officials have stepped up security to prepare for this weekend's 10th anniversary of the attacks.
Channel 9 reporter Andrew Doud was at Charlotte Douglas International Airport on Friday morning, where travelers will notice an increased security presence this weekend.
"I always seem to fly around this weekend for the last couple of years, so it's been fine since so I'm not too worried that anything's going to happen," said passenger Ashley Carpenter.
Despite the specific threats on New York and D.C., Homeland Security Secretary Janet Napolitano said there will be more air marshals on commercial airlines.
Airports are not the only ones taking additional security steps. Amtrak said they will be expanding patrols and bomb detecting teams.
They will also be stepping up screenings of passengers and baggage.