Secretary of Defense Gates summarized fundamental concerns with the practicality of the program concept: 
"I don't know anybody at the Department of Defense, Mr. Tiahrt, who thinks that this program should, or would, ever be operationally deployed.
The reality is that you would need a laser something like 20 to 30 times more powerful than the chemical laser in the plane right now to be able to get any distance from the launch site to fire ... So, right now the ABL would have to orbit inside the borders of Iran in order to be able to try and use its laser to shoot down that missile in the boost phase.
And if you were to operationalize this you would be looking at 10 to 20 747s, at a billion and a half dollars apiece, and $100 million a year to operate.
And there's nobody in uniform that I know who believes that this is a workable concept."

The Air Force did not request further funds for the Airborne Laser for 2010; Air Force Chief of Staff Schwartz has said that the system "does not reflect something that is operationally viable".

In December 2011, it was reported that the project was to be ended after 16 years of development and a cost of over US$5 billion.
While in its current form, a relatively low power laser mounted on an unprotected airliner may not be a practical or defensible weapon, the YAL-1 testbed is considered to have proven that air mounted energy weapons with increased range and power could be another viable way of destroying otherwise very difficult to intercept sub-orbital ballistic missiles and rockets.
On 12 February 2012, the YAL-1 flew its final flight and landed at Davis-Monthan AFB, Arizona, where it was placed in storage at the AMARG until it was ultimately scrapped in September 2014 after all usable parts were removed.

As of 2013, studies were underway to apply the lessons of the YAL-1 by mounting laser anti-missile defenses on unmanned combat aerial vehicles that could fly above the altitude limits of the converted jetliner.

By 2015, the Missile Defense Agency had started efforts to deploy a laser on a high-altitude UAV.
 Rather than a manned jetliner containing chemical fuels flying at 40,000 feet (12 km), firing a megawatt laser from a range of "tens of kilometers" at a boost-phase missile, the new concept envisioned an unmanned aircraft carrying an electric laser flying at 65,000 feet (20 km), firing the same power level at targets potentially up to "hundreds of kilometers" away for survivability against air defenses.
 While the ABL's laser required 55 kg (121 lb) to generate one kW, the MDA wanted to reduce that to 2–5 kg (4.4–11.0 lb) per kW, totaling 5,000 lb (2,300 kg) for a megawatt.
 Unlike the ABL, which required its crew to rest and chemical fuel to be reloaded, an electric laser would need only power generating from fuel to fire, so a UAV with in-flight refueling could have near-inexhaustible endurance and armament.
 A "low-power demonstrator" has been planned to fly sometime in or around 2021.

Boeing's Jim Albaugh sees it as a pretty good deterrent for the North Korean missile program if it was operational.
Secretary of Defense Gates summarized fundamental concerns with the practicality of the program concept: 
"I don't know anybody at the Department of Defense, Mr. Tiahrt, who thinks that this program should, or would, ever be operationally deployed. The reality is that you would need a laser something like 20 to 30 times more powerful than the chemical laser in the plane right now to be able to get any distance from the launch site to fire ... So, right now the ABL would have to orbit inside the borders of Iran in order to be able to try and use its laser to shoot down that missile in the boost phase. And if you were to operationalize this you would be looking at 10 to 20 747s, at a billion and a half dollars apiece, and $100 million a year to operate. And there's nobody in uniform that I know who believes that this is a workable concept."
The Air Force did not request further funds for the Airborne Laser for 2010; Air Force Chief of Staff Schwartz has said that the system "does not reflect something that is operationally viable".
In December 2011, it was reported that the project was to be ended after 16 years of development and a cost of over US$5 billion. While in its current form, a relatively low power laser mounted on an unprotected airliner may not be a practical or defensible weapon, the YAL-1 testbed is considered to have proven that air mounted energy weapons with increased range and power could be another viable way of destroying otherwise very difficult to intercept sub-orbital ballistic missiles and rockets. On 12 February 2012, the YAL-1 flew its final flight and landed at Davis-Monthan AFB, Arizona, where it was placed in storage at the AMARG until it was ultimately scrapped in September 2014 after all usable parts were removed.
As of 2013, studies were underway to apply the lessons of the YAL-1 by mounting laser anti-missile defenses on unmanned combat aerial vehicles that could fly above the altitude limits of the converted jetliner.
By 2015, the Missile Defense Agency had started efforts to deploy a laser on a high-altitude UAV.  Rather than a manned jetliner containing chemical fuels flying at 40,000 feet (12 km), firing a megawatt laser from a range of "tens of kilometers" at a boost-phase missile, the new concept envisioned an unmanned aircraft carrying an electric laser flying at 65,000 feet (20 km), firing the same power level at targets potentially up to "hundreds of kilometers" away for survivability against air defenses.  While the ABL's laser required 55 kg (121 lb) to generate one kW, the MDA wanted to reduce that to 2–5 kg (4.4–11.0 lb) per kW, totaling 5,000 lb (2,300 kg) for a megawatt.  Unlike the ABL, which required its crew to rest and chemical fuel to be reloaded, an electric laser would need only power generating from fuel to fire, so a UAV with in-flight refueling could have near-inexhaustible endurance and armament.  A "low-power demonstrator" has been planned to fly sometime in or around 2021.
Boeing's Jim Albaugh sees it as a pretty good deterrent for the North Korean missile program if it was operational.
Boeing YAL-1