At Burlington International Airport, beefed-up security Thursday forced passengers to rid carryon baggage of bottled water, lotions and even containers of maple syrup in response to a foiled terror plot in London.

All domestic flights in the United States were put under an "orange" alert -- one step below the highest level -- after the plot was foiled.

At Vermont's main airport, Kathy Gilman, 49, of New Haven, was putting her 10- and 12-year-old nieces on a flight to Washington, D.C., when they were told they couldn't take the two containers of "Pure Maple Syrup" they were taking home to their mother as souvenirs.

"When we got up there, they wouldn't let them take it," said Gilman, holding the small jugs in her hands. "Now, we'll send it to them in the mail."

One of the girls also had to dump "her expensive face wash," said Gilman.

But like most passengers here, she wasn't worried about terrorism striking.

Unlike other airports, flights were running on time and passengers appeared to be moving steadily through security checkpoints. Motorists dropping off or picking up passengers at the curb in front of the terminal were being quickly shooed away by attendants.

Airport officials said early Thursday that no flights were affected, but later in the day couldn't say whether there had been delays in incoming flights. Dan Brugger, a customer service representative for United Airlines at the airport, said that carrier had experienced no delays -- inbound or outbound -- except for flights routed to Chicago, where weather was a problem.

The airport has no direct service to Canada or the United Kingdom.

Passengers were cooperating, said airport director Brian Searles.

"My sense, having observed it this morning, is that many of them knew about it before they arrived. Some did not. They were cooperative, very accepting of the fact that extra security was in place. I didn't sense any negative reaction," Searles said.

Airport officials put lined wastepaper baskets at the checkpoints to accommodate the disposed liquids.

"They've emptied this thing at least 10 times today already," said security attendant William O'Neill, who was checking boarding passes at one of the airport's two security checkpoints. "It's mostly bottles of water, but a little bit of everything."

Nearby, Susan Bulmer, 47, of Washington, sat in a terminal chair, guzzling water from a thermos as she awaited the start of a trip to Wisconsin. "I'm drinking my water up now. I can't take liquids on," she said.

"I have contact (lens) solution in my eyeglass case. I don't know if they'll make me dump that out," she said.

But she wasn't ruffled by the heightened security. Most passengers here weren't.

"I'm leaving from a small airport where security is as high as it is at a larger airport," said Dave Towers, 52, of Rochester, Minn. "People are calm here, which improves the overall attitude."

Some were put out, though.

"It's overkill, if anything," said Bill Callnan, 57, of Middlesex, on his way to a gate for a flight to Philadelphia.

Bruce McDonald, federal security director for the Transportation Security Agency in Vermont, said baby formula, medications and breast milk were being allowed in carryon bags.

As for maple syrup?

"Maple syrup is a Vermont staple, you can't do without it," he said. "It is kind of funny, but maple syrup being one of these dark-consistency liquids. It's one of the things we'd naturally look at."

Neither the Vermont State Police nor Vermont National Guard were asked to increase their patrols or raise security alerts as a result, even though many transatlantic flights pass through Vermont airspace en route to East Coast destinations, officials said.

Gov. Jim Douglas, who was alerted early Thursday about the foiled plot, said Vermont residents shouldn't be afraid to fly.

His advice: "Pack lightly in terms of carry-on luggage and get to the airport earlier than you otherwise would."