Thousands of businesses could receive clearance to fly drones two years from now under proposed rules that the Federal Aviation Administration unveiled Sunday, a landmark step that will make automated flight more commonplace in the nation's skies.

Meanwhile, the White House on Sunday issued a presidential directive that will require federal agencies for the first time to publicly disclose where they fly drones in the United States and what they do with the torrents of data collected from aerial surveillance.

Together, the FAA regulations and the White House order provide some basic rules of the sky that will govern who can fly drones in the United States and under what conditions, while attempting to prevent aviation disasters and unrestrained government surveillance.

The FAA's draft rules would make it relatively simple for real estate agents, aerial photographers, police departments, farmers and anyone else to fly small drones for work purposes. Operators would need to pass a written proficiency test, register the drone and pay about $200 in fees — but would not have to obtain a regular pilot's license or demonstrate their flying skills.

The long-awaited regulations — the FAA had been drawing them up for several years — are expected to lead to a revolution in commercial aviation. But they must first undergo a lengthy period of public review and comment that is projected to take at least until early 2017. Once the rules are finalized, the FAA estimates that more than 7,000 businesses will obtain drone permits within three years.

"We're putting forward what we believe to be the safest possible approach at the moment, but of course we look forward to hearing back from the public," Transportation Secretary Anthony Foxx told reporters Sunday on a conference call.

The proposed regulations carry some significant limitations. Businesses would be allowed to fly drones only during daylight hours. And drones would have to remain within eyesight of the operator or observers posted on the ground.

The drones could fly no more than 100 mph and would have to stay below an altitude of 500 feet to avoid the risk of colliding with other aircraft. They would also be prohibited from flying over bystanders not directly involved in their operation.

As a result, companies would not be permitted to fly drones over long distances. That would effectively preclude companies such as pizza makers, Amazon.com and newspaper companies from delivering goods to customers' doorsteps via drone. The rules, however, are expected to be modified and loosened over the coming decade as drone technology advances.

Unlike with regular aircraft, the FAA would not require drone operators or manufacturers to certify in advance that the drones are safe to fly. Michael Huerta, head of the FAA, said such a requirement is unnecessary because small drones "pose the least amount of risk to our airspace."

The regulations would apply only to drones weighing 55 pounds or less. The FAA is still drafting rules for larger drones, and those are expected to take several more years.