Tuesday's terrorist attacks have some leading aviation experts calling for improved technology and beefed-up surveillance at US airports -- regardless of privacy advocates' concerns. The hijackers who crashed jets into the World Trade Center in New York and the Pentagon in Washington on Tuesday morning were reportedly armed with knives and would have had to pass through numerous airport security checkpoints at Boston's Logan Airport and Washington's Dulles Airport. Some experts say that cutting-edge security systems could have prevented the catastrophe -- the worst terrorist act in US history. Although no high-tech system could completely eliminate all terrorist risk at the nation's 450 commercial airports, more sophisticated devices could help make airport security far tighter than it is today. "Travelers will see increased security measures at our airports, train stations and other key sites," Transportation Secretary Norman Y. Mineta said in a statement Wednesday. "There will be higher levels of surveillance, more stringent searches. Airport curbside luggage check-in will no longer be allowed. There will be more security officers, random identification checks." Security experts are particularly bullish on face-recognition technology and other so-called biometric security devices. Biometrics is the digital analysis of biological characteristics such as facial structure, fingerprints and iris patterns, using cameras or scanners and computers that in some cases are as small as a computer mouse. Biometric devices have already made inroads in the United States. Orlando's Disney World uses hand recognition to prevent visitors from sharing season passes. Welfare offices in San Diego use fingerprint-recognition software to make sure recipients do not collect benefits more than once. New York's JFK airport uses hand scanners, but the purpose is to speed frequent flyers through customs -- not terrorist surveillance. Last month, the Alabama Bureau of Investigation (ABI) spent $660,000 for 30 fingerprint-scanning systems from Visionics, one of the largest makers of identification technologies. The ABI will use the technology to submit fingerprint and demographic records electronically to the Criminal Justice Information Center in Montgomery. Biometrics is especially in vogue among security agencies and government authorities abroad. In Swindon, England, some automatic bank tellers use iris scanners to verify customers. A security company in Sydney, Australia, has integrated fingerprint scanners into armoured trucks. Officials at the 1998 Nagano Winter Olympics in Japan scanned the retinas of security guards before outfitting them with rifles and ammunition. Aviation experts say face recognition is perhaps the most promising biometric technique for overcrowded airports because it relies on far-away cameras to identify people -- not finger scanners or other devices requiring people to click, touch or stand in a particular position. According to the 31 August edition of Computers Today, face recognition is expected to be one of the fastest-growing biometric market segments over the next three years. American authorities launched their most high-profile installation of face-recognition technology in January at Tampa's Raymond James Stadium, where police scanned the crowd for criminals or terrorists at Super Bowl XXXV. Authorities found 19 people whose mugs matched those of known criminals, but all of them were wanted for minor offences. Several months after the Super Bowl, the Tampa Police Department installed 36 security cameras with face-recognition software in Ybor City, a downtown entertainment zone. Tampa's experiment, which cost the city about $30,000 in new software, is the biggest sustained effort by a US police department to track criminals in a public zone. Aviation experts say biometrics has not caught on in airports because the devices, though relatively inexpensive, would consume time and space in jam-packed airports and possibly result in more airplane delays and cancellations. In one of the first major installations of face-recognition technology at an airport, authorities installed cameras and computers at Keflavik International Airport in Iceland in June. Airport police say the cameras and computers will help them to identify known criminals, potential terrorists on secret-service rosters and false asylum-seekers from the European Union. Part of the problem with biometrics is that it has come under intense scrutiny from privacy advocates, including Marc Rotenberg, executive director of the Electronic Privacy Information Center. The American Civil Liberties Union blasted face-recognition technology at the Super Bowl, insisting it created a "virtual lineup" of innocent Americans; Republican House Majority Leader Dick Armey dubbed it "snooperbowl." Increased airport security could also become a thorny issue for flyers who must endure the nation's overburdened air-traffic system. Some aviation experts say the cost of all the delayed and canceled flights throughout the nation exceeds $5bn a year. Already, more than 650 million passengers a year pass through US airports, and the figure is expected to jump more than 50 percent within a decade, according to the Federal Aviation Administration. Asking delayed passengers to withstand more waiting so they can file through additional checkpoints, finger scans or other devices could result in more "air rage" -- a new phenomenon in which weary fliers become violent after sustained delays or cancellations, some say. But it's unclear how Tuesday's attacks -- which could result in thousands of deaths and cost the United States billions of dollars -- could change the surveillance debate. Some experts say the horrific attack could make Americans much more tolerant of "Big Brother" cameras -- and of longer lines through metal detectors or even finger and iris scanners at airports. "People are always willing to give up liberties when they feel threatened," said Dr. Jeffrey Tiel, associate professor of philosophy at Ashland University in Ashland, Ohio, an expert on military ethics and terrorism. "If they think there's a chance they're going to be on a hijacked plane that gets crashed into a building, there's no question that people would put up with more hassle at the airport." Although many security experts hail biometrics, they are also quick to admit that technology cannot provide a magic bullet for the nation's considerable airport security woes. Face recognition relies on FBI or Immigration and Naturalization Service documents with photos of suspected terrorists. Similarly, outdated computers and technology at US consular agencies abroad could fail to spot the most notorious criminals. Even the most advanced bomb-detection device could not have stopped the terrorists on Tuesday: They essentially used airplanes as bombs and may not have brought any explosives through the airport. And improved metal detectors -- among the most low-tech devices in an airport -- would not have detected the weapons used by the terrorists in Tuesday's attacks. They allegedly used plastic or composite-material knives that metal detectors could not identify as potentially dangerous. Neither does technology solve the bigger human problem of human indifference toward airport security. Small, independent companies -- which typically pay workers little more than minimum wages and suffer turnover of 200 percent or more per year -- dominate the airport security industry. An official with the General Accounting Office (GAO) told a Senate subcommittee during a May 2000 meeting that the airline industry suffered from a workforce that "had made little progress in improving the effectiveness of airport checkpoint screeners." Another federal audit on workers at six airports determined that 19 percent had not had their backgrounds checked. "Screeners are not adequately detecting dangerous objects, and long-standing problems affecting screeners' performance remain," testified Robert Hast, the assistant controller general for the GAO. He added that GAO agents using fake badges and identification walked unescorted through security checkpoints; neither the agents nor their carry-on bags were screened. Some aviation experts say federal agents should supervise airport checkpoints, and some go so far as to recommend armed, federal supervisors onboard flights. "The technology is only as good as the people who use it...It's a mind-numbing experience to watch 300 bags cross the screen and try to determine if that's a hair blow-dryer or an explosive device," said aviation expert Paul Dempsey, director of the Transportation Law Program and professor of law at Denver University. "It should be handled by people who are police trained and certified in a meaningful way instead of a third-party company paying very low wages." Have your say instantly, and see what others have said. Click on the TalkBack button and go to the ZDNet news forum. Let the editors know what you think in the Mailroom. And read other letters.