Human in the loop is so twentieth century.
Tactical lasers, when deployed, will be human on the loop. Human’s confirm the threat and give the kill order. Everything else is machine driven- target location using a locate beam, firing on the right return signal.
Do I understand correctly that typically, when dealing with lasers, the shooter has to be bigger than the target in order to have enough power? Could a fighter generate enough power to take out another fighter at 100km?
Is it possible to make surfaces laser-resistant?
That has nothing at all to do with the efficiency of the LASER and everything to do with the efficiency of the targeting system. If you used the same system to fire a bullet, then you’re going to drastically increase the efficiency of the kinetic rounds. The kinetic rounds will be more efficient than the laser weapon if all else is equal. You can’t just give the laser weapon an insanely efficient targeting system and then claim the laser is more energy efficient.
Who mentioned energy efficiency? Did I? Where and in what context?
Human on the loop would make kinetic rounds more accurate in swarming situations, for sure. They would not be more accurate at range with realistic delay to target. Tactical laser ranges are not being disclosed, but they are multiple kilometers, not hundreds of meters.
The DoD is not pursuing tactical lasers because the are cool and they want to have the coolest air force. The utility (and requirements) for tactical lasers is derived from multi-million dollar wargames in which the introduction of tactical lasers show a significant impact.
You are right that even for base protection against swarms, it is not going to be human beings in the equivalent of a video games. It will be sophisticated targeting systems guiding smart bullets against fast moving smart UAS munitions.
I’m not in that industry, so I cannot (and were I, certainly would not be able to) tell you details of what is being developed or procured. But even a quick search on Wikipedia reveals systems like the naval AN/SEQ-3 laser CIWS and Lockheed HELIOS that are apparently safe/cheap enough to work with and good enough to complement point defense against UAS and rockets, even if we are not talking about taking fighters and tanks out at 100 km.
What the others have said. Lasers have effectively zero time of flight. The targeting systems just consists of a radar identification and a mirror that aims at the target. For shooting down another aircraft, the human just presses the button. For shooting down incoming missiles or drones, probably not even that.
“Efficiency” is starting to be a weird way of describing the laser’s advantages, so let’s just call it a figure of merit. The figure of merit here would be the mass needed to disable one enemy. And we have to distinguish between fixed mass and marginal mass. The laser has a pretty high fixed mass but a low marginal mass, so it’ll be relatively more effective against swarms.
Another advantage is cost. “Bullets” here are really often discardable-sabot rounds with tungsten cores and cost tens of dollars each. So a typical kill may cost thousands. A laser needs less than a dollar’s worth of kerosene.
So, these lasers systems are really only intended to replace CIWS like the Phalanx and not SAMs?
Wonder what sort of countermeasures there could be against that? A laser can’t be spoofed with chaff or flares. Perhaps the only defense would be to prevent oneself from being locked on in the first place.
I don’t think anyone knows yet how it’ll all play out, because it depends on how the technology continues to develop. But CIWS systems are a great place to start since they are used repeatedly and can pay for a high fixed cost (either on the ground or a ship). A SAM replacement would be a step above that, with significantly higher power required (aircraft are bigger than missiles) and a lower repeat rate. And an aircraft-aircraft weapon has even more stringent requirements, needing that power level in a much lighter package. Still, it doesn’t seem like these are insurmountable obstacles.
Chronos mentioned it. Had you read the thread, you would have realized the context of my post. Chronos said that kinetic munitions are more efficient method of delivering energy to a target than laser weapons. Dr. Strangelove argued that most bullets miss their targets (by a factor of hundreds), so this reduces their efficiency. My counter to this argument was that bullets miss because of many factors that are not necessarily or inherently removed from the equation when using lasers. Therefore, from an efficiency perspective, it is not fair to say “bullets miss by the hundreds but lasers won’t”. A laser that is aimed and fired the same as a bullet will miss almost as much as the bullets do. Bullets that are aimed and fired by an advanced targeting system would not inherently “miss by the hundreds”. So, when factoring for efficiency, a fair test would use the same target(s) and the same targeting system(s).
That was the conversation you jumped into.
It’s much easier to counter a laser right now. A simple smoke screen is enough to cripple it.
Smoke screens are one counter tactic that won’t be real practical in aerospace applications. Though it certainly can be for ground combat vehicles and some waterborne ops.
True. But.
The F-35 for example already has a problem with overheating. There are reports that during low level high speed flight in hot weather between frictional heating, ambient air temperatures, insolation, and the amount of avionics & hydraulic systems waste heat being dumped into the fuel tanks they’re already cooking the fuel up to problematic temps after a reasonable time in the air. There’s no more heat capacity left to absorb excess laser energy.
FWIW, I agree with your characterization of the discussion. Of course, I disagree with the implication that lasers do not have significant and obvious targeting advantages compared to bullets.
The AN/SEQ-3 CIWS mentioned above has a video (see link) demonstrating the capabilities. It works exactly as one would hope: you aim at the target and turn on the laser. It can easily track the target, and doesn’t miss.
The Phalanx is a conventional CIWS, and uses 100+ rounds for a kill:
The 20–mm APDS rounds consist of a 15 mm (0.59 in) penetrator encased in a plastic sabot and a lightweight metal pusher.[13] Shells fired by the Phalanx cost around $30 each and the gun typically fires 100 or more when engaging a target.[14]
The AN/SEQ-3 isn’t powerful enough to replace the Phalanx, but the limit doesn’t seem to be tracking, just sustained power. Another order of magnitude or two in power and it will be competitive.
To be fair, there will be more scifi laser weapons in the air by 2035 than F-35s. 
That’s fair, but still: another 100 kW at a low duty cycle isn’t going to “break the bank”, so to speak. For the power levels that a fighter jet operates at (whether talking about turbine power or heating rates or just about anything else), an extra few kW is completely negligible.
At any rate, a boiling water cooling system is probably superior in this case.
But an airplane can’t do that. An airplane is always flying forward. If it generates a smoke screen, it will fly past and through its own smoke screen, leaving it behind.
Just stay in the clouds.
Or fly away from the guy shooting at you, so “flying forward out of your smoke screen” still puts it between you.
Or, for that matter, be in a war zone. There’s usually lots of smoke in those, inherently. War materiel that doesn’t work in a war isn’t very practical.
OTOH, it remains highly profitable. Very high tech weapons that don’t actually work in anger are not exactly a new thing. That last thing a weapons manufacturer wants is an actual war. All the wild promises and carefully coordinated tests are revealed for what they are.
Countermeasures to a laser weapon are something that does not seem to have been explored much. Missiles could be gold plated. Aircraft could reasonably be coated with an ablative. Aiming systems can be blinded or spoofed. There is an entire field of work in such areas.
I suspect that lasers might find a useful role in shooting down small drones and the like. The threat posed by swarms of tiny UAVs is something left field of current thinking, and a system that can quickly disable lots of them quickly might be valuable. But aircraft engaging in SciFi dogfights with laser weapons seems fanciful.
Counter measure: projectile covered in corner reflectors. Reflect enough light back into the laser to damage it.