UPS has unveiled its plan for delivery drones: build them right into trucks, and launch them at various points along their route.

The delivery company ran an initial test on Monday, when it claims to have successfully launched a drone from the top of a truck, let it autonomously deliver a package, and then return to the truck at a different location.

While that test might have been successful, UPS’s system is still far from being ready for delivery. TechCrunch reports that a second test of the drone failed, with the drone aborting its own launch, falling over, and nearly getting crushed.

Still, it’s a relatively novel take on how delivery drones could work. Rather than focus on replacing drivers, UPS wants to augment its drivers with drones to ease their workload, particularly when it comes to reaching out-of-the-way places.

Mark Wallace, an engineering executive at UPS, says that in rural areas, “our package cars often have to travel miles to make a single delivery.” The company estimates that it could save up to $50 million per year by cutting a mile off of every driver’s route each day. That phrasing makes it all sound pretty easy, but it adds up to about 66,000 miles per day.

UPS hired a company called Workhorse to build the drone and truck used in its test. The truck looks like a relatively standard brown delivery van, but on the inside, there’s space to store and load a drone. When the drone is ready for launch, the top of the truck slides open so that it can fly out. UPS says the drones can fly for up to 30 minutes and carry up to 10 pounds.

There’s clearly more to be done on the drone-development front, but UPS is limited on the regulatory front for now, too. The Federal Aviation Administration still requires drones to remain within their operator’s line of sight, which means they can’t yet depart from a truck all that far.

But the technology is advancing industry-wide, and the regulatory situation is being pushed forward, however slowly, by companies’ desire to put drones to work. Amazon has been the most public about its plans to use delivery drones — it started testing in the UK last year — and even 7-Eleven has gotten in on the action.