HOHENFELS, Germany—The U.S. Army is embarking on its largest overhaul since the end of the Cold War, with plans to equip each of its combat divisions with around 1,000 drones and to shed outmoded weapons and other equipment.

The plan, the product of more than a year of experimentation at this huge training range in Bavaria and other U.S. bases, draws heavily on lessons from the war in Ukraine, where small unmanned aircraft used in large numbers have transformed the battlefield.

HOHENFELS, Germany—The U.S. Army is embarking on its largest overhaul since the end of the Cold War, with plans to equip each of its combat divisions with around 1,000 drones and to shed outmoded weapons and other equipment.

The plan, the product of more than a year of experimentation at this huge training range in Bavaria and other U.S. bases, draws heavily on lessons from the war in Ukraine, where small unmanned aircraft used in large numbers have transformed the battlefield.

The Army’s 10 active-duty divisions would shift heavily into unmanned aircraft if the plan is carried out, using them for surveillance, to move supplies and to carry out attacks.

To glean the lessons from Ukraine’s war against Russia, U.S. officers have debriefed its military personnel and consulted contractors who have worked with the Kyiv’s military about their innovative use of drones.

“We’ve got to learn how to use drones, how to fight with them, how to scale them, produce them, and employ them in our fights so we can see beyond line of sight,” said Col. Donald Neal, the commander of the U.S. 2nd Cavalry Regiment. “We’ve always had drones since I’ve been in the Army, but it has been very few.”

The effort to integrate drones was on full display in February when a brigade from the 10th Mountain Division battled against a mock opponent here. During the Cold War, the huge Hohenfels training range was used to prepare for armored warfare against a potential Soviet attack on Western Europe.

But in an updated scenario reflecting new combat tactics used in Ukraine, small drones buzzed in the gray winter skies controlled by soldiers and defense contractors in the muddy fields below.

The bitter cold caused ice to form on some of the aircraft’s rotor blades and sapped the batteries, a glitch that hadn’t arisen in earlier exercises in Hawaii and Louisiana. Soldiers rushed to recharge them as they sought to keep the unmanned aircraft aloft.

Ukrainian and Russian troops have clashed with artillery, armored vehicles, manned fighters and other conventional systems. But it is drones that have transformed the conflict because they are cheap, can attack in swarms to overwhelm defenses, and can send live video feeds to the rear that can make it difficult to hide on the battlefield, analysts said.

“Land warfare has transitioned to drone warfare. If you can be seen, you can be killed,” said Jack Keane, the retired general who served as vice chief of staff of the Army and observed the exercise here. “A soldier carrying a rocket-propelled grenade, a tank, command and control facilities, artillery position can all be taken out by drones very rapidly.”

Drones are just one capability the Army plans to field as the Army seeks to buttress its ability to deter Russia and China after decades of fighting insurgencies in the Middle East and Central Asia.

The service is also developing ways to better link soldiers on the battlefield, drawing on cellphones, tablets and internet technology, and is acquiring a new infantry squad vehicle. The Army plans to invest about $3 billion to develop better systems for shooting down enemy drones and is moving to build up its electronic warfare capabilities.

Altogether the overhaul would cost $36 billion over the next five years, officials said, which the Army would come up with by cutting some outmoded weapons and retiring other systems—steps that will require congressional support.

The “Army Transformation Initiative,” as the service’s blueprint is known, comes as Elon Musk’s Department of Government Efficiency has been seeking to slash spending and personnel across the government.

Gen. Randy George, the Army chief of staff, and Daniel Driscoll, the secretary of the Army, met with Vice President JD Vance recently to explain that the service had a plan to upgrade its capabilities while making offsetting cuts, a Pentagon official said. Defense Secretary Pete Hegseth endorsed the plan in a directive signed this week.

“We aren’t going to ask for more money,” George said in an interview. “What we want to do is spend the money that we have better.”

The Army is halting procurement of Humvees, its main utility vehicle for decades, and will no longer purchase its Joint Light Tactical Vehicle. It is also stopping procurement of the M10 light tank, which has proven heavier and less useful than planned when the program began a decade ago. It is also planning to retire some older Apache attack helicopters. A reduction in civilian personnel will also contribute to the savings.

Three brigades—the 3,000 to 5,000 soldier formations that make up divisions—have already been outfitted with some of the new unmanned systems, and the goal is to transform the rest of the active duty force within two years, Driscoll said in an interview. A division typically has three brigades.

Army divisions that haven’t begun to incorporate the new technology typically have about a dozen long-range surveillance drones, which were first deployed more than a decade ago.

The Marines have done away with their tanks as part of a separate overhaul that calls for small missile-toting combat teams to hop from island to island in the Western Pacific to attack the Chinese fleet in a conflict.

The Army plan, which is intended to boost the service’s capabilities in Asia as well as Europe, still envisions acquiring new tanks, long-range missiles, tilt-rotor aircraft and other conventional systems.

The American industrial base will have to increase to produce the latest off-the-shelf technology that the Army wants. Last year, Ukraine built more than two million drones, often with Chinese components, U.S. officials say. But the U.S. military isn’t allowed to use parts from China.

Write to Michael R. Gordon at michael.gordon@wsj.com