The battlefield in Ukraine must teach the Pentagon a valuable lesson: Small drones are the future of warfare.  

Yet the US military has been pouring hundreds of millions of dollars into systems, from improved radar to laser weapons and missiles, that would be little use against the latest generation of attack drones appearing in Ukraine’s skies.

There may be a better way.

Critics complain the US Army is far behind the drone-warfare curve.

Just last month a new manual of tactics for tank platoon commanders suggested using the tank’s main gun to bring down incoming drones — and that in the event of a drone attack, a tank commander should sit out of the turret hatch and warn other tanks via hand signals.

These are laughable instructions in the face of the Ukraine war’s signature weapon, the first-person-view drone.

FPV drones are racing quadcopters converted into miniature guided missiles.

These drones are agile and fly at high speeds. Even if it’s spotted in time, hitting one with a tank gun would be like trying to swat a fly with a sledgehammer.

FPVs can destroy a tank in multiple hits, often giving the crew time to escape — but sitting outside the armor would be suicidal.

FPVs, costing just a few hundred dollars each, have flooded Ukraine’s battlefield, and their ability to hit targets 12 or more miles away from their operators has been a major contributor to the current stalemate.

Scout drones flown by both Ukraine and the invading Russians spot any moving vehicle, and FPVs attack it before it can advance.

Supply vehicles are a favorite target; according to a recent estimate, two-thirds of FPV strikes are now on the roads rather than the front lines.

Both sides now lie low and dig deep, hiding in trench systems protected by anti-drone netting.

Kyiv aims to build 4 million drones this year — enough to target individual foot soldiers.

And now they can do it from ambush.

Battery-powered FPVs can only fly for about 20 minutes. Operators “perch and stare” to save juice, landing their drone on a building or on the ground where they can watch a road or track used by the enemy.

When a target appears, the FPV lifts off and attacks.

A compilation video from one Ukrainian drone unit shows a series of ambushes, all in the same location: Each time a Russian patrol comes past, an FPV takes off from behind them from no more than 10 yards away.

The soldiers react, turning and raising their Kalashnikovs . . . too late.

Other videos show the target’s point of view.

In one, Ukrainians are driving down a track at high speed in a buggy when a Russian FPV lifts off ahead of them.

A desperate chase follows, with the Ukrainians shooting the drone out of the air before it can hit them. Many troops now carry shotguns to counter FPVs.

Small drones keep evolving. Some are now fitted with the sort of miniature solar panels backpackers use to keep their phones charged. These power the drone’s camera and communications without draining the battery.

The solar-powered drone can lurk in ambush for as long as the sun is up, and start again the next day.

In a sense these drones are just the latest version of mine warfare — but these are mines that can find their way anywhere, relocate themselves and attack from a distance.

The current generation must be controlled by a human operator, but we’re already seeing AI-powered autonomous FPVs in Ukraine.

In another year the battlefield may be infested with smart, solar-powered killer drones.

Where is the US military in this futuristic world of drone warfare?

On July 10, Defense Secretary Pete Hegseth signed an order to  “unleash US military drone dominance” and make procurement quicker and easier.

Yet the US Army is only buying around 6,000 FPV-type drones in the current budget year. Ukraine uses that many every day, and Russia is catching up to that mark.

American plans to bring down attacking drones with missiles or lasers look impractical when ambushers can appear at such close range.

The Ukrainians are already developing their solution: They’re sending small bombers ahead of vehicles or troops to find waiting ambush drones and drop grenades on them.

Soon to come is an AI-powered drone that can automatically detect ambushers on the ground. Sweeps by automated drones could keep the roads clear.

More important, though, Ukraine is leading by example, keeping up with drone warfare’s rapid evolution as each development demands a countermeasure.

The Pentagon has traditionally relied on big-money, high-tech solutions developed by American companies.

But a willingness to embrace cheap technologies developed rapidly by friends and allies might save a lot of lives when US troops are featured in some future round of drone videos. 

David Hambling is the author of “Swarm Troopers: How Small Drones Will Conquer the World.”