The retail wars are heading to the skies.

Walmart has applied for a patent for a giant, floating distribution center, according to details published last week by the U.S. Patent and Trademark Office. The application, which was first spotted by Bloomberg, revealed a blimplike aircraft that would hover between 500 and 1,000 feet off the ground and send drones to deliver customer packages.

The vessel could operate autonomously or with a human pilot on the ground. It would have several launching stations for sending out its delivery drones.

Amazon was granted a patent for a similar distribution aircraft back in April 2016. That patent included fewer specifics than Walmart's, instead offering a more general description of the floating distribution center concept.

The two companies have been upping the ante in their retail battle recently. Amazon expanded its physical stores, and Walmart focused more on its online business by offering Amazon-esque perks like free two-day shipping.

Controlling every step of the delivery process would save both companies plenty of time and costs. For years, Amazon has been testing different solutions for last mile delivery, which refers to the final leg of a package's journey to your door. While Jeff Bezos's company currently relies on logistics companies like Fedex or the U.S. Postal Service, it's been experimenting with drone delivery in the U.K. since last year. Amazon recently received a patent for software that could be used by self-driving trucks, and the company reportedly has a secret team working on developing driverless delivery technology.

Walmart is following suit in trying to change its delivery logistics. Drones could make deliveries faster by bypassing traffic, and an air-based distribution center could be easily relocated based on demand, which can vary widely. It could also serve a wider area than a fixed distribution center: the ship could fly from town to town, sending drones to deliver packages. Then, once the goods have been dropped off, they could fly back to restock for the next delivery round.

Bloomberg reports the Walmart patent stands a good chance of being approved, given that it goes into more detail than Amazon's. While Amazon's makes no specific mention of a fuel system, the Walmart patent describes a system that would use gas power.