If you have European friends who travel a lot, you probably know this: Nobody actually admits that they like Ryanair.

They say they don't like the added fees, or the far-flung airports, or the hard yellow plastic, or the lack of seat back pockets. They don't like the nickel-and-diming. They don't like the jingle they play on the planes every time they land.

But there are two things people do seem to like, which is why Ryanair is one of the great success stories of European aviation: 

First, they like the ridiculously low base fares. Second, they like the airline's total lack of political correctness (and blunt honesty about its business model).

Now, thanks to the company's chief marketing officer, we have it all combined, in a single blunt, simple phrase: "We're low cost, mean bastards."

Can you imagine the CEO of Southwest Airlines, Gary Kelly, or Oscar Munozof United Airlines saying something like this?

Heck, Munoz was praised for transparency just for admitting that his airline "got it wrong" when one of its flight attendants forced a passenger to store a live dog in an overhead bin.(The dog, a French bulldog named Kikito, died during the flight. Maybe you heard.)

But, speaking "with characteristic Irish bluntness," as the folks over at Quartz put it (hey wait, isn't that a little bit racist?), Ryanair's CMO, Kenny Jacobs spelled it all out.

The context was Jacobs' talk at Skift Forum Europe, which was a travel industry conference in Germany last month. Ryan claimed at the event that Ryanair's fleet made it "the "greenest airline in the world," if you judge it on CO2 emissions on a per-passenger, per-mile basis.

(He said "per-kilometer" because they're in Europe, but it's the same argument.) Here's his math:

1. More passengers on each flight.

Ryanair sells and fills 96 percent of the seats on its flights. More passengers on the same plane means fewer CO2 emissions per passenger.

2. New airplanes.

Ryanair's planes are newer than its compeition, Jacobs said, and more efficient.As Quartz put it: "Compared to a regional competitor like British Airways--which has an average fleet age of 13.8 years--Ryanair's average fleet age is 6.8 years."

3. They fly point-to-point.

That means they fly fewer total miles (okay fine, kilometers) than competitors who use a hub system.

4. The fly green approaches.

This is a technical way of flying that pilots can use to reduce the amount of fuel it takes to get the plane down and bring it to a stop. It was pioneered by the Swedish airline SAS.

Of course, it's basically impossible to fact-check these claims without being able to calculate every other airline's vacancy rate, fleet age, etc. But with Ryanair, it does pass the smell test anyway.

Why? Not because the're doing it out of the goodness of their heart, or because they care about the environment more than other people, or even because they think it would be especially good PR.

Instead, they're doing it because it shaves costs. Or as Jacobs put it in his full quote:

"We've got the youngest fleet in the world for two reasons: we're the fastest growing airline and we're low cost, mean bastards. So, we want to have young aircraft because they're cheaper to maintain and the engines use less fuel."