To squeeze laser into things like airplanes, we're going to have to make the weapons much smaller and more efficient than the boat-sized platforms we've got right now. DARPA is hard at work on a system called Excalibur that's small enough and powerful enough to make an aircraft like this a reality.
The easiest way to make a beastly powerful laser is by using giant vats of toxic chemicals. This is how Boeing's YAL-1 airborne laser works, which is why it's the size of a 747. Using 747s as jet fighters is somewhat impractical, so DARPA has been working on ways to decrease the size and increase the efficiency of lasers that can convert electricity directly into laser energy.
DARPA's Excalibur prototype is 10 times lighter and more compact than existing high-power chemical laser systems. As you can see from those single-inch scale bars in the pics, it's really very tiny, and could easily be stuffed into one of the current generation of fighter jets or drone aircraft.
It gets crazier, though: the end goal of systems like these, which combine arrays of independent lasers into one single beam, is to reduce the size of the emitters enough such that they can be mounted all over the skin of the aircraft. Then, to fire the weapon, all the emitters turn on and point themselves at the target, teaming up to deliver the maximum amount of power.
By the end of this year, DARPA is hoping to demonstrate a three-kilowatt prototype, with the eventual goal of a 100 kW system that could be used for "precision strikes against both ground and air targets."