WASHINGTON — Routine use of small drones by real estate agents, farmers, filmmakers and countless other commercial operators was cleared for takeoff by the Obama administration Tuesday, after years of struggling to write rules that would both protect public safety and free the benefits of a new technology.

The Federal Aviation Administration announced the creation of a new category of aviation rules designed specifically for drones weighing less than 55 pounds. The long-anticipated rules mean commercial operators can fly drones without special permission.

Industry and government officials describe commercial drones as the biggest game-changing technology in aviation since the advent of the jet engine.

“This is a watershed moment in how advanced technology can improve lives,” said Brendan Schulman, a vice president at DJI, the world’s largest civilian drone-maker.

Jason Miller, an Obama economic adviser, said the rules are the first step toward full integration of drones in the national airspace system.

Until now, commercial operators have had to apply for a waiver from rules that govern manned aircraft, a process that can be time-consuming and expensive.

Since 2014 the FAA has granted more than 6,100 waivers and another 7,600 are waiting for approval. Many more small companies have been using drones without FAA permission, say industry officials.

Unless those operators make a serious mistake that brings them to the FAA’s attention, there’s not a lot the agency can do to track them down. The new rules would provide an easier way for those businesses to operate legally.

The rules also would effectively lift the lid on flights by other potential operators who have held off using the technology – ranchers who want to count cattle, research scientists, and companies that inspect infrastructure like bridges, oil platforms and smokestacks, to name a few.

Under the new rules, operators would register their drones online, pass an aviation knowledge exam for drone pilots at an FAA-approved testing center and then they’re good to go. That’s a big change since operators currently have to have a manned aircraft pilot’s license.

Operators also would have to follow many of the rules that apply to model aircraft hobbyists like keeping drones within sight at all times and not flying over people or higher than 400 feet.