Amazon has officially won the Federal Aviation Administration’s approval to test delivery drones in the United States.

In a letter posted on the agency’s website, the FAA gave the green light as long as the drones fly within the height and speed requirements: No higher than 400 feet and no faster than 100 miles per hour.

Paul Misener, Amazon’s Vice President of Global Public Policy, hailed the announcement:

We’re pleased the FAA has granted our petition for this stage of R&D experimentation, and we look forward to working with the agency for permission to deliver Prime Air service to customers in the United States safely and soon.

The approval is a major victory for the e-commerce giant which has previously expressed frustration with the FAA’s slow pace in approving commercial drone testing.

Drones for delivery have been criticized by opponents concerned about potential threats to public safety and privacy.

FAA administrator Michael Huerta told PBS NewsHour’s Miles O’Brien in January that the agency is moving slowly because of the safety challenges posed by commercial drone use.

“A bedrock principle of aviation is see and avoid. And if you don’t have a pilot on board the aircraft, you need something that will substitute for that, which will sense other aircraft, and we can ensure appropriate levels of safety,” Huerta said. “We have the opportunity to do it quickly, or we have the opportunity to do it right. We’re very focused on doing it right, so that we don’t in any way compromise safety.”

There’s been an explosion of same-day or sooner services, including the promise of home delivery by drone. But there’s debate about how many customers are really interested in ultra-speedy delivery. Economics correspondent Paul Solman reported in early April.

Amazon’s last request for drone tests in the US was in limbo for over six months and the company subsequently developed a test site in Canada. When the FAA issued approval in March, the company stated that the prototype drone had already become obsolete, Reuters reported.

Amazon CEO Jeff Bezos first announced the drone-delivery venture in 2013. Amazon’s Prime Air service seeks to use self-piloted drones to deliver packages to its customers over distances of 10 miles or more within 30 minutes.

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