Inside Miami International Airport, it looked like business as usual on Tuesday and Wednesday, with perhaps more heavily armed police officers patrolling the concourses. They are there as a deterrent and to react, if needed.
"Anything can happen, so we need to be on our toes. We need to be alert. We need to be responsive and we need to make sure that the traveling public understands that when they come through this airport, they will be safe," said Emilio Gonzalez, Director of the Miami-Dade Aviation Department, who also oversees operations at MIA.
The FBI and the Department of Homeland Security have warned American police departments that terrorists could try to copycat the Paris attacks. However, the bulletin says there's no specific threat that they know of.
"The bad guys only have to be right once, and that's something that we have to guard against constantly. We take this very seriously," Gonzalez said.
The U.S. State Department issued a global travel advisory, which is the kind of thing most travelers just shrug off.
"Can't do anything about it, just gotta stay positive," one traveler said.
The FBI advises everyone to be vigilant, alert and stay away from crowded places, especially if they're traveling overseas. That doesn't mean stay home and cower in a corner.
"Gotta still travel, you know? Shouldn't allow terrorist threats or reports to change what you're gonna do for the holidays," said Cory Akers, traveler. "Still gotta enjoy life."
Airlines advise travelers, over the next week, get to the airport two hours early, even for domestic flights, because they're expecting such long lines at the TSA checkpoints.
The worldwide travel alert will be in place until the end of February 2016.