A new generation of plane-sized autonomous delivery vehicles is capable of carrying hundreds of pounds for hundreds of miles. They’re called cargo drones. They are fast, more environmentally friendly, and could completely change the cargo industry.

Delivery drones are being tested today that are designed to drop a single item nearby a target, which is a more local solution. Over the past few months, Amazon announced plans to drop packages at customers’ doors, Alphabet’s Wing got FAA approval to make deliveries in the US, and UPS said it was testing its own tech by delivering medical supplies to hospitals in Northern Virginia. But there are concerns about safety and how the Federal Aviation Administration will regulate them.

Cargo drones could offer more dynamic and environmentally friendly shipping options

Cargo drones offer similar benefits of speed and a reduced carbon footprint but on a much larger scale. Instead of sending truckloads of goods on a set schedule, cargo-carrying drones can ship fewer items more often but with less of an impact. Focused on rural areas and shuttling goods between distribution centers, cargo drones are designed to land in the water or take off vertically, making drop-offs even more flexible.

They’re coming in all shapes and sizes, too. For example, Boeing’s cargo air vehicle weighs 747 pounds, has eight rotors that allow for vertical flight, and can carry payloads of up 500 pounds. California-based startup Sabrewing is working on a prototype that can achieve speeds of up to 180 knots (207 miles per hour) with a cruising altitude as high as 22,000 feet. Another startup, Natilus, is working on a 30-foot prototype that’s about the size and weight of a military Predator drone.

Each of these companies have spent years developing high-capacity, long-range drones in secret, but there’s a race to get to the skies first. Natilus, Sichuan Tengden Technology, and Elroy Air aim to be operational by 2020. Elroy Air’s autonomous Chaparral system is hoping to be used for medical supply delivery, disaster response, and remote military missions. But the company also sees potential in partnering with FedEx, DHL, or UPS for package deliveries. According to David Merrill, CEO of Elroy Air, building drones at this scale has been a huge investment, but there is still hope that it will pay off.

Morgan Stanley estimates that autonomous urban aircraft could become a $1.5 trillion industry by 2040. That includes everything from vertical take-off and landing (VTOL) aircraft, flying taxis, military unmanned aerial vehicles (UAVs), and delivery drones. But if delivery drones have shown us anything so far, it’s that getting people used to the idea of packages being shuttled back and forth overhead might not be easy: 54 percent of Americans polled in a 2017 Pew Research Center survey disapproved of drones flying near residential areas.