Business travelers going to LAX and other Southern California airports were bracing themselves for long delays Thursday following the arrests of 20 suspected terrorists in Britain accused of plotting to blow up trans-Atlantic jetliners.

News of the foiled plot prompted U.S. authorities to declare the nation's first-ever Red, or Severe, security threat level to all commercial flights originating in the United Kingdom bound for the United States. The threat level also was raised to Orange, or High, for all domestic flights.

Five airlines Air New Zealand, American Airlines, British Airways, United Airlines and Virgin Atlantic Airlines operate 20 daily non-stop flights between London-Heathrow International Airport and LAX. Those flights had not been cancelled.

Passengers were being order to dump all liquids and gels prior to clearing security British authorities said that the suspects were planning to blow up the jetliners using liquid or gel explosives. The order and additional searches at the gates caused lines to swell and delays at LAX for both leisure and business travelers coming in and out of the airport.

At an 11 a.m. news conference, Los Angeles Mayor Antonio Villaraigosa sought to reassure travelers that LAX was safe.

"We have no information indicating that LAWA facilities or flights are targeted in any terrorist plots," the mayor said.

Villaraigosa indicated that airport police, the Los Angeles Police Department and other security agencies were operating under increased security measures that have become standard for Code Orange threats.

Nico Melendez, a federal Transportation Safety Administration spokesman at LAX, advised that prior to leaving for the airport all travelers should check with their airlines to ensure flight times and delays, regardless of the traveler's destination.

Melendez, as well as other local travel authorities, have also advised that sticking to the traditional "two-hour rule" to have sufficient time to make all flights on time. However, Villaraigosa at his news conference recommended travelers arrive at LAX three hours before their departure time to ensure they don't miss their flight.

Other local airports, such as Burbank, which has seen a surge in business activity over the last year, are also suggesting that travelers arrive earlier than expected noting that security lines at Burbank airport are averaging about 30 minutes.

"Business travelers normally arrive here right-on-time," said Victor Gill, spokesman for Burbank's Bob Hope Airport. "That won't cut it today or in the immediate future. Two hours should be enough time for most travelers to check in and clear security."

As for long-term affects, Michael Collins, the executive vice president of L.A. Inc., the city convention and tourism bureau, said that though delays are expected well into the foreseeable future, no long-term dips in tourism or business travel are likely to be seen.

"We've seen over the years that the major deterrent to travel is the perception, by travelers, of danger. We're not seeing that now," he said. "Travel is still safe; it's just a lot slower now."

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