The US Department of Homeland Security is paying for tests on defensive laser systems designed to thwart attacks from shoulder-fired missiles on passenger airliners, the New York Times reported Sunday.
DHS has spent up to now 120 million dollars on the tests, which are expected to last through 2006, the Times reported.
Many US officials believe that inexpensive shoulder-fired missiles such as the US-made Stingers and Soviet-made SA-7's will soon become a threat within the United States.
The US Congress has ordered DHS to quickly move to adapt military technology for the 6,800 US commercial jets.
Estimates range from 10 billion dollars to install systems in all US commercial jets, and up to 40 billion over 20 years when maintenance and upkeep are included, according to the Times.
The system uses plane-mounted sensors to detect heat-seeking missiles, then automatically fires infrared lasers to jam the missiles' guidance systems.
The system would operate within an 80 kilometer (50-mile) area around airports when planes land or take off, the Times reported.
DHS officials have said there are currently no credible threats of domestic missile attacks.