Overseas and at home, the U.S. government has pioneered the use of drones for military, intelligence and law-enforcement purposes. But while other countries have applied drones—usually smaller, simpler, cheaper ones—to everything from package delivery to film-making, mining, agriculture and environmental protection, the U.S. has blocked their use by private entities. At least until March 6, when Raphael Pirker won in federal court.

Mr. Pirker’s legal journey began innocently enough, when he became involved in the small but intense world of hobbyists who use radio-controlled drones to record the most stunning bird’s-eye video of Earth’s landmarks. In late 2010, he flew a small drone around the Statue of Liberty’s crown, more than 200 feet above Liberty Island. The video went viral online and Mr. Pirker realized that he could turn his hobby into a business.

Soon trouble came. In 2011 the Federal Aviation Administration slapped him with an unprecedented $10,000 fine after he used a drone to record a promotional video of the University of Virginia campus. The FAA charged that he had operated without a license and flown recklessly close to buildings, cars in a tunnel and pedestrians.

In his defense, Mr. Pirker noted that his drone—a five-pound Styrofoam model airplane—caused no injury or damage.