ORLANDO, Fla. -- This time of year, Orlando's tourism industry depends on British tourists. But at Orlando International Airport, passengers were dealing with tight security and long delays Thursday.

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Police in Britain arrested 21 people suspected of plotting to blow up planes bound for the United States. As a result, security check points are fully staffed at airports across the U.S., including OIA. Additional Transportation Security Administration workers were called in early Thursday morning. They're prepared to work extended work shifts and all vacation requests, for now, are out of the question.

"Due to heightened security requirements, the TSA is prohibiting liquid items beyond security check points," a voice said over the loudspeaker at OIA on Thursday morning.

"Nothing liquid can go through security. They're taking it from everybody"said flight attendant Cari Kelly. "Even us."

By order of the Department of Homeland Security, travelers will no longer be allowed to carry liquids, creams gels or of anything else of similar consistency on the airplane. Those items must be checked until further notice.

"It's now 7:50 and hasn't even made it through the checkpoint yet," said John Riddle.

Riddle said he dropped his wife off at 6:10am. The lines were so long, she missed her 7:50am flight to Billings, Montana.

"They have a very difficult job. I understand that. It's very stressing for them today. But when you watch how the line moves, and then you watch the people who walk in front of the line saying they're late for a flight, so the people in line are almost penalized for being on time," Riddle said.

But not everyone will be inconvenienced by the added screening measures. Passengers with prescribed medication won't be required to check that in, and people traveling with small children will be allowed to carry on baby formula.

Officials at OIA recommend travelers arrive at least two hours early for domestic flights and at least three hours early for international flights.