Air power has been a decisive advantage in recent wars (e.g. Desert Storm).
Seems possible/probable that the victor of future wars will be determined by who has the better drone air-force.
Since it is already insanely expensive to run wars like the one in Afghanistan, if you can bump the cost up over the tipping point then you "win" by your opponent being unable to afford the cost. This was how the Afghans "beat" the Soviets, and how the US "won" the cold war. (scare quotes because in neither case did the Soviets surrender to an opposing force, they just stopped participating in the war effort.
So if the US has to spend a couple billion dollars a month to make war against an enemy that is spending 100 million dollars a month, eventually the US loses.
Anyway, line of sight medium range lasers are really here, and long distance (hundreds of KM) feasible.
Stick one of these every 100km round your borders and try flying an aircraft overhead.
Air power may soon be just another casualty of the march of progress - and the billions it costs to run an aircraft carrier may seem a little expensive.
But line of sight lasers are bound by terrain. Swarms of very low flying, very small drones would defeat such a system.
Or drones inserted directly inside the country via spaceplane, avoiding the border lasers.
This kind of thing isn't limited to aircraft. Once ground vehicles/drones have an automated turret that will immediately return fire, (or fire first depending on the kind of war) humans in front line combat might not work so well.
First, you figure out how long it takes a laser installation to lock onto and destroy a drone. Let's say it take five minutes. You then build a bunch of cheap, $100 decoy drones that have no payload or remote control capability. You send decoys through at a rate of ten per minute, overwhelming the laser system. Amongst the decoys, you send a real drone or two. You adjust the decoy rate and number of drones until you've calculated that you have a 99% chance that a real drone gets through.
Granted, your costs have gone up an order of magnitude, since you need to spend so much money on decoys. On the other hand, drones are just going to keep getting cheaper and the decoys even more. Besides, if you use your first couple of drones to destroy the laser, you don't even have to worry about decoys after that point.
Airplanes do more than keep away other airplanes. They're also useful to blow up the enemy ashore, close air support for the grunts, deep tactical missions to isolate the battlefield.
You're still going to need flying machines. Need some way to get them close to the battlefield. This might not Ford class super carrier but it's going to be _some_ kind of carrier.
Let's say you wanted to protect the west coast of the U.S. You'd deploy 80 or 90 of these things (underwater, of course) along the shore. Every so often, one would surface, illuminate the skies with powerful radar, take out several targets, then disappear. Maybe it all happens inside of ten minutes. Then it relocates. Now picture that happening over a wide area with scores of ships.
My numbers might be off, but you could get total coverage and not really present a target for counter-attack. And maintain that coverage for months or years without having to worry about refueling, port calls, a logistics train, or personnel issues.
Lasers will change things in a big way, including creating completely new types of ships.
The gun won't see incoming until they pop over horizon which is .. what five miles away?
Now I am armchair warrior-ing - but I at least spent a few years as an enlisted guy, a long time ago.
This is purely educated guess, but my guess is that lasers make the problem much much easier and hence much more effective.
Instead of needing to calculate a trajectory of the inbound aircraft, predict its future location (i.e. where the puck is going to be), and correctly calculate a trajectory for the intercept missile, you can probably just assume all that away because lasers travel at the speed of light. As long as you can get a fix on where the aircraft is right now, point the laser, pull the trigger.
1. Distance Chemical lasers are proven at hundreds of miles 2. Time Speed of light. Dodge, counter measures, evasion. Pah! 3. Reusability Missiles run out quick, electricity from a generator less so
Shoot a stealth drone the same way you shoot stealth planes - visually
Along the lines of your analysis, I wonder if we won't start seeing low-observable drone ground forces.
http://singularityhub.com/2010/07/25/armed-robots-deployed-b...
But at the end of the day, everything loses against a single nuclear bomb.
But death comes from above.