Zach Phillips at Government Executive reports on efforts to guard American airplanes from MANPADS -- shoulder launched missiles originally conceived to allow infantry to gain protection against air strikes, but that pose extreme threats to civilian aircraft that are "relatively slow and fly predictable routes, emit large heat signatures and descend to low altitudes miles away from the airport."
The whole concept, however, seems fundamentally misguided. "The government requires a price tag of less than $1 million per unit in quantities of 1,000 units, . . . but even a price below $1 million per unit adds up to a lot of money when installed on hundreds or thousands of airplanes, and neither DHS nor Congress has said who would pay for the technology, a key issue for the financially struggling airline industry." You need to think that through. We're talking about spending billions of dollars to protect airplanes against a threat that, so far in human history, has taken down zero civilian aircraft (once two missiles "narrowly missed an Arkia Israeli Airlines flight taking off from Mombasa, Kenya.") What's more, not only does the price seem high relative to the risk, but the payoff sounds minimal.
A shoulder launched missile is a highly lethal device that an imaginative terrorist in possession of one could sure use to blow a bunch of stuff up even if security measures made it completely impractical to fire them at airplanes. I don't want missiles crashing into office towers or Amtrak passenger trains or what have you. Insofar as there's a real MANPAD problem out there, it seems like it needs to be addressed by preventing the flow of unauthorized missiles into the US, not by equipping planes with inordinately expensive countermeasures.