(CNN) -- Travelers expressed both relief and concern about the death of Osama Bin Laden, the terror mastermind who changed airport security forever after the September 11, 2001, attacks.
Bin Laden's killing brought immediate global travel warnings even as many fliers pondered whether the terror threat they've had to worry about for almost a decade would ultimately subside.
Passengers on board El Al flight 27 from Tel Aviv -- the first international flight to arrive Monday morning at New Jersey's Newark Liberty International Airport -- found out about the news when they touched down.
"It gives a greater feeling of security knowing there's one less person who wants to kill people," said Manny Landau.
But other passengers wondered what's next.
"The people on the flight started saying, 'Well does that mean the cells will be more active? Will there be revenge actions?' You know, we worry," said Kira Sirote, who witnessed the attacks on the World Trade Center on September 11, 2001.
But Sirote and a dozen other passengers on the flight who spoke with CNN said they had no intention of changing their travel plans.
The U.S. Department of State, however, warned U.S. citizens traveling and living abroad to be on alert for the "enhanced potential for anti-American violence."
The agency also strongly urged U.S. citizens "in areas where recent events could cause anti-American violence" to limit their travel outside of their homes and hotels and avoid mass gatherings and demonstrations.
No new airport alert
But Bin Laden's death doesn't necessarily mean travelers will see stricter security at the airport.
The Department of Homeland Security remains at a heightened state of vigilance, but does not intend to issue an alert at this time, said Secretary of Homeland Security Janet Napolitano in a statement.
"We will only issue alerts when we have specific or credible information to convey to the American public," Napolitano said.
"However, our security posture, which always includes a number of measures both seen and unseen, will continue to respond appropriately to protect the American people from an evolving threat picture both in the coming days and beyond."
CNN's Allan Chernoff saw no noticeable change to security at Newark International Airport on Monday.
Still, the Port Authority of New York and New Jersey -- which owns and operates airports including Newark International, JFK International and LaGuardia -- said it was increasing police presence at its facilities.
The response was not based on a current threat, but out of an abundance of caution and all facilities would remain fully operational and at normal service levels, the Port Authority said in a statement.
Security experts said the government is trying to avoid being overly alarmist about any threat, but wants travelers to be aware about their surroundings.
"I think what we're likely to see is some fairly amateurish attacks over the next maybe two to three weeks. Certainly U.S. interests primarily abroad, so U.S. visitors and workers who live overseas should be particularly careful," said Michael Barrett, former director of strategy for the White House Homeland Security Council.
"We certainly want to be prepared and it's just important that all Americans are a little extra vigilant."
Meanwhile, other countries were quick to follow the U.S. Department of State in issuing a travel alert. The Australian government on Monday warned its citizens about an "enhanced risk of anti-Western violence" following bin Laden's death.
Britain's Foreign and Commonwealth Office urged British nationals overseas to "monitor the media carefully for local reactions, remain vigilant, exercise caution in all public places and avoid demonstrations, large crowds of people and public events."
CNN's Allan Chernoff contributed to this report.