Rep. John Mica said he would try to pass legislation over the next 90 days to pay for research and development and for outfitting some planes with technology to thwart a missile attack. Mica, R-Fla., put the cost of the equipment at $1 million per plane.

"We can't afford not to act," said Mica, chairman of the House Transportation and Infrastructure subcommittee on aviation.

But such equipment is very expensive and is not always completely effective, Homeland Security Department spokesman Brian Roehrkasse said.

Mica spoke right after a closed hearing with counterterrorism experts to discuss the threat posed by shoulder-fired missiles.

Among those who testified were Rodney Ratledge, Defense Intelligence Agency analyst, and Eric Arnett, Central Intelligence Agency analyst, transportation officials and the Israeli ambassador. Representatives from defense contractors Raytheon and Northrop Grumman also appeared.

"I came in somewhat skeptical," Mica said. "What we saw was pretty sobering."

Major airlines are struggling financially — two of the biggest are in bankruptcy — and say they cannot afford the added costs of new security measures. Mica and Oregon Rep. Peter DeFazio, the subcommittee's ranking Democrat, said the government should pay for the anti-missile devices.

"Ultimately, this is not about cost," said Michael Wascom, spokesman for the Air Transport Association, which represents major airlines. "It's about our defense and intelligence agencies conducting a threat assessment and reaching an informed conclusion that such a proposal should or should not be advanced."

The threat posed to commercial planes was driven home in November when terrorists fired two SA-7 missiles that narrowly missed an Israeli passenger jet after it took off from Mombasa, Kenya. Officials concluded that al-Qaida probably was behind the attack, which coincided with a bomb blast at a nearby hotel.

Hundreds and perhaps thousands of Soviet-style SA-7s — heat-seeking rockets that can hit low-flying aircraft within 3 miles — are said to be available on the worldwide arms market.

DeFazio said older missile launchers can be bought for as little as several thousand dollars. But he is more concerned about the proliferation of newer, more accurate models.

Though no specific threats involving the portable missiles have been identified, there is concern that such weapons could be smuggled into the United States and used against aircraft.

Sen. Barbara Boxer, D-Calif., and Rep. Steve Israel, D-N.Y., introduced legislation this year to require on-board missile defense systems on all 6,800 planes in the U.S. commercial fleet. Boxer testified the bill would cost as much as $10 billion.

That is almost as much as the Transportation Security Administration's total costs for aviation security in the two years after the Sept. 11 terrorist attacks, agency spokesman Robert Johnson said.

DeFazio, though, said the government could equip some planes with the devices and some with dummies. Representatives from private industry said planes could be outfitted in a matter of months, Mica said. He would not estimate the cost because it would indicate how many countermeasures would be deployed.

There are several kinds of defense systems that divert or confuse the missile: small decoy flares, infrared jammer devices, high-powered lasers, chaff or packets of heated foil and towed decoy targets.

Transportation Security Administration chief James Loy said the United States is working to limit trafficking in the devices and to destroy the older, less-effective models.