It's not that simple. The airline has to agree to let him fly without a passport, and assurances from Ecuador that he'll be allowed to enter might not be enough to convince them to to that. Also, there probably aren't any direct flights from Moscow to Quito, so he'll need cooperation from some other country, and possibly another airline as well. That's conceivable, but might not work out, and Snowden probably wouldn't know that it's not working out until he was in handcuffs.

Ecuador has several national airlines, in particular TAME. They could charter a flight with them if they actually wanted to.

Which they don't.

They could also ask a diplomat to escort him.

A charter flight from Russia to Ecuador costs hundreds of thousands of dollars and approaches the distance limits of private jets. I doubt they even do this for themselves.

Huge difference between allowing someone entry to your country and the government paying to fly a jetliner across the world for one person.

what, you don't think that Ecuador is capable of chartering a private plane to fly from Moscow to Quito?

They don't.

Like I said: Lip service. They like to talk, but when it comes to action nothing happens.