There have not been reports of any major delays, however.
A spokesman for the New York Port Authority said, "I've not been told of any unusual delays today but we recommend passengers arrive with extra time given everything that is going on. There is no specific guideline but given such circumstances get there a little early."
Many travelers have decided to cancel their travel plans over terrorist fears. Multiple airlines, including Delta, American and British Airways announced that they will waive cancellation fees for the week.
DialaFlight said they are going to work with customers.
"We are also going through every airline policy regarding refunds or alterations to their routes, and are actively contacting airlines who have yet to release a policy to find out what can be done for our clients," they said.
America is on high alert after the Boston Marathon bombings, resulting in an increase in reports of suspicious packages.
Downtown Seattle was shut down after people reported a suspicious backpack abandoned on a sidewalk, and New York City Police had 77 reports of suspicious packages in less than 24 hours.
Hotels are also upping their security, as many are only allowing visitors to enter elevators if they show a room key first.
"We are taking all necessary and appropriate steps to ensure the safety of our guests across our portfolio," Ken Cruse, CEO of Sunstone Hotel Investors, said.
New York has deployed critical response teams to monitor highly trafficked areas.
Mayor Michael Bloomberg said, "We are asking all New Yorkers to remain vigilant in the days ahead. If you see something that looks strange, just pick up the phone and say something. But at the same time, we refuse to let cowardly acts of violence stop us from living in our city, the city that we love."