The terror threat posed by missile attacks against commercial airplanes has prompted the U.S. government to test antimissile systems on American aircraft, following the lead of Israel, which began installing similar systems on its El Al fleet last weekend.
Since 1983, there have been at least five shoulder-fired missile attacks on large civilian planes, according to a study by the Congressional Research Service in November 2003. Two of the planes were hit, killing 171 people, the report said.
The system Israel is installing on its passenger fleet uses hot flares that draw heat-seeking missiles away from the jet engines.
It is designed to defeat hand-held shoulder-fired missiles, a weapon that proved successful last November when a DHL cargo plane flying over Baghdad took a direct hit.
"In Israel they're about to protect all of their commercial airlines," said Sen. Barbara Boxer, D-Calif. "Why wouldn't we do the same?"
The United States is years behind Israel in terms of such countermeasure technology, but now the Department of Homeland Security is aggressively searching for its own system.
Three Systems in Development
There are three contenders. BAE Systems, a defense contractor, is developing a high-tech laser jammer.
"You start with an eyeball, if you will, a vigilant piece of equipment that's looking around the aircraft at all times. It's sensing a missile launch," said BAE Systems project manager Burt Keirstead.
Within seconds of sensing a missile, a laser beam is directed at the missile to jam its guidance system, sending it right into the ground.
Northrop Grumman, another contractor, is building a similar system.
A pod the size of a canoe containing four detectors and a laser is mounted on the belly of a jumbo jet. When fired in tests, it also sends missiles spiraling out of control.
"[The detectors] can see all the way around the aircraft," said Robert Del Boca, vice president of Northrop Grumman. "We will protect the aircraft, 360 degrees."
The government is also studying a flare system in a joint project led by United Airlines.
Unlike older flares that burn hot, causing security concerns, the system in development uses newer flares that don't burn at all. Instead they oxidize, creating short burst of heat.
Next month, Homeland Security officials will choose one or two of the systems and begin an 18-month study aboard commercial test planes.
"I think five years from now, we will probably see these on some planes," said Penrose Albright, assistant secretary at DHS for science and technology.
Installing countermeasure systems on all 6,800 of the country's commercial planes is projected to cost $10 billion to $30 billion. Cash-strapped airlines will not be able afford the price tag, so the expense will be passed on to either taxpayers or passengers.
ABC News' Bob Woodruff filed this report for World News Tonight.