The US government has given a thumbs up to commercial drones but with some potentially crippling restrictions for would-be delivery firms including an effective ban on flying over urban areas.

The new rules follow a lengthy consultation process by the Federal Aviation Administration into what it formally calls “small unmanned aircraft systems.” The FAA first began working on permission for drones to fly in controlled airspaces way back in 2008.

Under the new rules, drones must be operated by a specific pilot with a license for the particular drone, and must remain within their eyeline at all times without the use of binoculars or telescopes. Pilots must pass a test every two years to renew their license.

As a condition of the commercial license, the drone must weigh less than 55lbs including any payload, must fly below 400 feet and cannot exceed 100 miles per hour. It can only fly between 30 minutes before sunrise and 30 minutes after sunset.

Even if the line of sight rules weren’t enough to put the kibosh on proposed delivery services from Amazon and Google, another rule makes such services largely redundant for now. The licensing specifically prohibits the drone from flying above any person other than the operator and a delivery recipient, meaning it would be as good as impossible to get deliveries to urban areas.

The new licensing only applies to commercial operations. Amateur operators have been legally required to register their drone and label it with an identification number since December.