Last night, Amazon CEO Jeff Bezos went on "60 Minutes" and announced that Amazon's R&D department is working on drones that can deliver packages within 30 minutes. He called the service Amazon Prime Air.

The thing is, Amazon Prime Air won't be available for many years.

Even Bezos said last night that the earliest Amazon Prime Air could be in service is 2015 because that's the soonest the FAA could update its laws.

But The Wall Street Journal reports that the FAA isn't planning on beginning the certification of commercial drones until 2020.

There is a good reason for this. Drones can be very dangerous.

In March 2013, a commercial airliner flew within 200 feet of a small drone flying at 1,750 feet over a neighborhood in New York. The collision would have killed hundreds of people.

A retired commercial pilot named Tom Jeffries told ABC15.com the airliner almost hit the drone because drones don't appear on radar.

Jeffries says: “You’re never going to see them until they hit something. When they suck one of those drones into the engine of an airplane, then it’ll get everybody’s attention.”

The fact is, there is a very good chance that, last night, Amazon "announced" a service that will never exist in reality.

Why did Amazon do that?

The answer is free advertising. Even better: free advertising the night before the biggest e-commerce shopping day of the year, Cyber Monday.

How much was that free advertising worth?

"60 Minutes" gave more than 15 minutes to its Amazon story. A 30-second spot during the 7 p.m. show usually costs just over $100,000.

If you figure Amazon got 30 30-second commercials' worth of time, you can estimate that it got about $3 million worth of "earned" media.

But $3 million is probably a very low estimate. That's just the cost Amazon would have had to pay to reach "60 Minutes'" 13 million viewers. Thanks to all the coverage Amazon Prime Air has gotten in other outlets, many more millions of people are talking about the company today.

The funny thing is, talking about "drones" is a fairly common PR stunt at this point.

After the "60 Minutes" show last night, a Hacker News reader compiled a list of previously announced delivery drone programs, many of which were also PR stunts: