At a southern Maryland airfield, Dr. Joseph Scalea watched a drone carrying a kidney in a cooler fly 3 miles.

The test flight, repeated 14 times, was the culmination of three years’ work by the University of Maryland Medical Center transplant surgeon, who sees the unmanned aircraft as the ultimate method for delivering life-saving organs from donors to recipients.

“I did a transplant where the organ flew 1,500 miles from Alabama on a commercial aircraft and it took 29 hours,” Scalea said. “That’s ridiculous. It could have been here in six. ”

Organs don’t last long outside the body, and delays and mistakes mean some lose quality or can’t be transplanted. Scalea is frustrated that the system relies on couriers, commercial airline schedules and costly charter flights arranged by local nonprofit agencies. He cited a recent $80,000 charter to deliver a liver to Baltimore from Texas and an unrelated case in which a heart was left on a commercial plane.

That led Scalea to try to jump to the head of a movement underway to resolve the technical, regulatory and medical hurdles to using drones to shepherd medical supplies such as blood, medicines and body parts, anywhere around the country at any time.

More than 30,000 organs are transplanted a year, and many more valves, bones and other tissues. Scalea expects drones to remake how organs are delivered in the next three to five years. “It will be faster and cheaper and more predictable,” Scalea said. “Drones really work for this purpose.”

The FAA strictly enforces limits on drone use, but the agency plans changes based on a program it launched in May with 10 local government agencies. The tests will help change the U.S. regulations, which are more stringent than those in developing countries, said Matt Scassero, director of the University of Maryland Unmanned Aircraft System Test Site in St. Mary’s County.

Another challenge is that drones capable of flying organs across the country aren’t yet commercially available, Scassero said. Such drones would have to be engine-powered rather than battery-driven. They also would need to have the ability to avoid obstacles and to carry a reliable method of preserving organs.

Scalea devised a system that can send real-time information on the condition of an organ to a transplant doctor’s cellphone during flight. The sensors fit inside a wrap like a beer koozie along with the organs.

Any final delivery system would likely rely on a range of technologies.

But the promise is huge. Such flights could avoid airline delays or traffic or even bad weather. Scalea, who has gone to pick up organs in his own vehicle, estimates that drones could reduce travel time by 70 percent on the farthest deliveries.

Dr. David Klassen, chief medical officer for UNOS, said computer programs do the matching and factor time among other parameters. He said drones could mean better matching and less waste. They also could contribute to more equitable allocation by directing organs to the sickest patients rather than being limited by geography. “It’s an intriguing idea. It won’t be simple.”

Doctors and engineers continue to work on aspects of those hurdles. A team at Johns Hopkins University has been working on coolers that could safely transport medical supplies such as blood, vaccines and other medications over long distances.

Stefano Di Carlo, head of operation support for Médecins Sans Frontières, said officials would like to move larger cargo farther. People in war zones likely would be wary because drones are also used as weapons, but poor areas lacking in infrastructure would be among the places most eager for such delivery.

“If the technology became cheaper, more reliable and easier to set up,” Di Carlo said, “the potential is huge.”