Drone delivery has yet to materialize in the way many had been expecting, with numerous autonomous flying machines zipping over city streets carrying packages to customers, but Wing is one company that’s as determined as ever to make it happen.

The Alphabet-backed enterprise has been steadily and quietly testing its flying machines and delivery systems for several years now, slowly gaining the confidence of regulators to let its machines fly further and more autonomously between base and delivery addresses.

In another expansion of its work, Wing on Wednesday announced plans to add a bigger drone to its fleet that it says will “simplify and streamline larger orders.”

In other words, where some orders by a single customer had previously required two aircraft, or two trips, to complete, the new larger aircraft will be able to do it in a single flight.

In an online post unveiling the new drone, Wing CEO Adam Woodworth explained how his team has created a so-called “Aircraft Library,” which works on a variety of configurations that can be quickly adapted whenever it identifies a need in the market, like a bigger drone for larger orders.

“It’s always been our vision to implement a multimodal drone delivery model, in the same way that ground delivery uses different vehicle sizes for different orders,” Woodworth said, adding: “With the new aircraft carrying more food, medicine, and household essentials, customers in urban and suburban areas will be able to bundle their orders better — and receive them in one quick trip.”

As with Wing’s existing fleet, the new aircraft has a round-trip range of 12 miles (19 km) and can cruise at a speed of around 65 mph (105 kph). But its standard cardboard delivery box can handle consignments of up to 5 pounds (2.3 kg) — twice that of its smaller machines.

The new delivery drone will join Wing’s fleet in the next 12 months, the CEO said.

Wing has so far used its drones to complete around 350,000 deliveries to customers’ homes in carefully selected locations across three continents. As part of its efforts to develop and test its platform, the company partnered with Walmart last year to launch a drone delivery service in the Dallas-Fort Worth area, flying items from two Walmart Supercenters to customers who placed orders using a mobile app. The goal is to reach delivery addresses within just 30 minutes of the order’s placement.

Wing says its drones “essentially fly themselves.” In other words, they’re highly autonomous but are monitored by remote human operators to ensure that the flight and delivery proceed without any problems.