"We have taken the steps we need to take to make sure everyone's in the loop on this incident yesterday and reminding them of the approach to this issue," Robert Johnson, spokesman for the Transportation Security Administration, said Friday. "We are engaged in responding to this issue and we have been since earlier this year."
"We've been expecting it we just didn't know where it was going to happen," security expert Joe Knoller told CBS News.
A former Israeli security advisor and now full time aviation consultant in the u.s., Knoller sees tell tale signs of al Qaeda, which has created instructional videos on surface to air missiles.
"They are very easy to use and very easy to hide," he said.
TSA Thursday notified security officials at airports of steps being taken by the federal government to counter the threat of a terrorist shooting down a plane from a portable launcher on the ground, Johnson said. He declined to describe what those steps were, citing security concerns.
It's the dirty little secret of aviation, reports Hughes. According to some security experts, airplanes have been vulnerable to a missile attack for some time, but security measures in and around airports have not been increased to prevent such an attack.
The TSA held a classified meeting with airline officials and others in the industry several weeks ago to discuss the danger posed by the missiles, which can be fired from rocket launchers light enough to be held on a person's shoulder, Johnson said.
The agency has jurisdiction from airports' perimeter fences and inward, although such missiles could be fired from farther away.
"The perimeter of security at airports has to be expanded to a wider circle," said Knoller.
Many other security experts still don't think it will happen in U.S.
"This is a risk I wouldn't place in the top ranks, said Todd Curtis of Airsafe.com, "simply because too many things have to go the way of the terrorist in order for anything to be hit."
Still, there have been more than 25 successful missile attacks against commercial jetliners around the world.
This past May, the FBI issued an alert to law enforcement that al Qaeda could attack a commercial airline in the u.s. because it had used the same tactic against U.S. war planes in Saudi Arabia.
"We take very seriously the fact that our opponents do have surface to air missiles," said Gen. Peter Pace, vice chairman of the Joint Chiefs of Staff, on May 30.
Many of those missiles came from the U.S. in the first place. Soldiers confiscated, or in some cases bought back, more than 5000 stinger missiles this year in Afghanistan. They were originally provided by the CIA to fight the Soviets. The military admits countless more have been sold to criminals and terrorists.
The main countermeasures to a missile attack include dropping flares or metallic chaff to confuse the missiles. Israel's airliners reportedly have these defenses, but they are an expensive fix for today's cash-strapped US airlines.
The military is reportedly considering a plan to fly specially-equipped fighter jets with missile-jamming lasers on board around airports — probably the cheapest and most immediate measure.