(AP Photo/Evgeniy Maloletka)

When a plane like Malaysia Airline Flight 17 is suddenly dropped from the sky by a missile attack launched from a vehicle no larger than a tank, the temptation is to look for the technology that will protect airline passengers from such threats. So should we be equipping commercial passenger planes with missile defense systems?

For about a decade, Israel has been trying to do just this. And the country's experience serves as an interesting test case.

In 2002, an Israeli charter flight flying at a height of 500 feet was attacked above Mombasa, Kenya, by a shoulder-launched missile. No one was hurt, but it prompted the Israeli government to begin searching for ways to protect its country's passenger planes and helicopters from the threat of so-called MANPADS, or Man Portable Air Defense Systems.

That produced a government project called SkyShield, powered by a program called C-MUSIC, for Commercial Multi-Spectral Infrared Countermeasures.  The program uses lasers and radar jamming, explains Adi Dar, the general manager for Elbit Systems, the Haifa-based lead contractor on the project that has worked for nearly a decade developing anti-missile technologies for passenger planes.

With MANPADS long believed to be the greater threat, commercial aviation missile defense systems have not been engineered to protect against longer-range surface-to-air missiles (SAM) like the Buk SAM believed to have been involved in the Ukraine attack.

But at any height targeting the head of a missile from a moving passenger plane is technologically complex, says Dar, a former Israel Defense Forces official. "It's like hitting a tennis ball with a laser from an aircraft that is moving 800, 900 kilometers per hour."

Israel has focused on fully-automated systems like lasers and radar jamming out of a belief that other, more manual techniques used in military settings, like the distribution of chaff -- small pieces of glass, metal, or plastic used to confuse tracking systems -- place too much of a burden on commercial air pilots.

There are other challenges, says Dar. Fuel consumption is a concern, as the anti-missile technology can create drag since it is attached to the aircraft's underbelly.

Elbit Systems, says Dar, has been deploying its countermeasure technologies among militaries in Germany, Italy, and elsewhere in Europe. And, he says, they've been working to protect heads of state and other "VIPs" around the world. But Elbit has not contracted with commercial airlines outside Israel.

But some experts doubt Israel's approach. Professor Theodore Postal, a professor of science, technology, and international security at MIT, thinks missile defense systems are largely futile. Especially given the increased sophistication of missiles designed to evade detection and destruction, argues Postal, protecting passenger planes from attack is "extremely difficult to do."

After all, "combat aircraft have pretty sophisticated electronic countermeasures," says Postal, "and they get shot down all the time."

Regardless, some U.S. lawmakers have pressed for this country to follow Israel's lead.

In the United States, both the 2002 Mombasa attack and the attacks of September 11th, 2001, increased interest in the protection of passenger planes. In May 2002, the FBI warned that "given al Qaeda's demonstrated objective to target the U.S. airline industry," the country should consider the possibility that shoulder-fired missiles could be used against U.S commercial aircraft.

Partly in response, in 2003, Senator Barbara Boxer (D-Calif.) and Congressman Steve Israel (D-New York) introduced the Commercial Airline Missile Defense Act. The bill would have required the Department of Defense to pay an estimated $1 million a piece to equip U.S. commercial passenger planes with anti-missile technologies. With 6,800 planes, the price tag would have been nearly $7 billion--a number that, no surprise, caused many to balk. The Defense Department took instead to nudging aircraft providers to explore adapting military anti-missile techniques for commercial use, which led to, among other things, Northrop Grumman's Guardian Anti-Missile program.

In Israel, the government picks up the cost of the SkyShield project, estimated by Dar to be at least a few hundreds of millions of dollars on research and implementation thus far. Elbit won't disclose what it costs to attach its anti-missile systems to aircraft, but Dar allows that it is in the neighborhood of "several million dollars" per plane. Israel, reports Elbit, has conducted successful tests of its anti-missile systems on Boeing 737s and Boeing 80os, including recent tests in southern Israel.

The cost is lower for Israel than it would be for the United States largely because of the size of its fleet. The three major airlines participating in SkyShield together own and operate about 40 planes. "We're not talking about Lufthansa," admits Elbit's Adi Dar, of the German airline that alone has nearly 300 planes. "We're a small country."

Faced with the potential costs of such a program, the trend in recent years in the United States has been a move away from anti-missile systems that place the responsibility for protection on airlines and pilots. The Department of Homeland Security's Project Chloe, named for a character on the television program "24," has begun exploring the use of missile-detecting and missile-defeating drones that would hover over U.S. airports.

And so, for now at least, wide-scale use of anti-missile technologies on commercial passenger planes remains largely limited to Israel.

"In Israel, " Dar goes on, "most of the government decided that the threat is real. And they decided to invest the money required. Other countries, other airlines have to be cost-effective in deciding what they want."

Update: This piece originally grouped Man Portable Air Defense Systems, or MANPADS, with the type of surface-to-air missile that is believed to be involved in the Ukraine attack. That has been corrected and a clarifying paragraph has been added.