EDITORIAL- Private Investigator Steven Rambam of New York City and Kerrville has done airlines and their passengers a huge favor.

Rambam is the man who, with an Express-News reporter and photographer watching, breached security at San Antonio International Airport three times last week. He was able to take a fake .38-caliber derringer past checkpoints in both terminals.

Security is Rambam's business and airport security is a personal concern of his, not only because he flies a lot, but also because he sees U.S. airports as vulnerable to terrorists. He has tested and helped improve airport security from Miami to Los Angeles. He also has done security work abroad.

No, Rambam isn't after the security contract in San Antonio. He says he has more work than he needs. After getting the fake gun past guards in San Antonio, he offered a free seminar to employees of Wackenhut Corp., the firm in charge of security. The offer was declined.

However, the Express-News story on Rambam and the fake gun apparently has had some results. The Federal Aviation Administration sent investigators to make a security check. More Wackenhut guards are on duty, presumably taking a harder look at people going through checkpoints on the way to airplanes.

More is at stake here than just San Antonio. Passengers boarding here are inside the security perimeter and can transfer to other domestic or international flights without being checked again. The assumption at other airports is that passengers were screened thoroughly in San Antonio.

No one about to take to the skies should complain about increased security. It is better to be inconvenienced than to be blown up at 30,000 feet or hijacked.

Airlines are responsible for airport security, and some take it more seriously than others. El Al, the Israeli national airline, inspects every piece of luggage before it goes into the cargo hold or the cabin. Passengers watch as the inspection is made. Swiss Air also checks all baggage.

Rambam has some sound ideas on improving security here and elsewhere, including trained and screened security people. The city should require the airlines responsible for security here to accept Rambam's offer of a free seminar.

The ghastly toll of the bomb aboard Pan Am Flight 103 is just the most recent reminder that better security is in everyone's best interests.