Airlines across the United States are imposing new security measures after Tuesday's hijackings, which brought down the World Trade Center and part of the Pentagon. Israel's national airline carrier, El Al, is known for its strict procedures.

After the terrorist attacks in New York and Washington, the U.S. Federal Aviation Agency imposed new rules on air travel, including no curbside check-in and no knives on planes.

Israeli officials they have already put those kinds of security measures in place. They say it is unlikely the hijackers would have been able to take over an El Al flight. The cockpits are tightly sealed and armed undercover marshals are always on board. Airline personnel are carefully vetted, their security clearances checked and updated frequently.

Defense Ministry spokesman and former El Al security official Shlomo Dror says it usually takes about 15 minutes to check in passengers but he does not offer any details.

When you have the names of the passengers, you can check them, you can see if they are on the list," said Mr. Dror. "When they come to the airport, [there is a] very short but good, effective check. And if there is some kind of suspicion, you will have a much better security check."

Passengers who fly El Al are accustomed to stringent security measures, which start even before check-in. They wait patiently - most of the time - while security personnel carefully check through luggage. They respond to a series of questions like: Who packed your bags? Were they with anybody else? Were you given anything by anyone to bring to your final destination? El Al personnel use profiling to target potential troublemakers. They do not just single out Arabs. They often quiz women traveling alone since an Irish citizen was discovered in 1986 carrying a homemade bomb for her Palestinian boyfriend. Mr. Dror says some passengers have complained about the extra time it takes to check in for an El Al flight. But, he says, the extra minutes are worth it if a potential terrorist attack can be averted. "If you have good security they will choose other targets because they want to succeed," he said.

Despite all the security measures, Israel's Transportation Minister and former army general, Ephraim Sneh, closed Israeli air space for 24 hours after the U.S. terrorist attacks, just to be on the safe side.

"What we are doing is a better, more thorough questioning of passengers and a more strict surveillance of their luggage and a permanence of security officers on our flights. I'm sure that the lessons of Tuesday morning will be learned in all those aspects of how passengers should be cleared and what the security procedures inside the cabin should be," said Minister Sneh.

Israel spends nearly $100 million a year on security for air travel. Security officials like Shlomo Dror say it is less than it costs for airlines to train pilots and flight attendants. And, Mr. Dror adds, every dollar is well spent.