Which, from what I've read, was an error. They actually wanted him to get on an aircraft, fly over Europe, and then when he flew over the skies of a US ally that ally would force the aircraft to land. Then the US would extradite him from there.

But they lost track of Snowden, panicked, and cancelled his passport. Leaving him stuck in Russia of all places (which is actually worse for the US than either a South American country OR HK, as they have zero political capital there).

They didn't revoke his passport when he was in Russia, they revoked his passport the day before he left Hong Kong [1]. He traveled to Russia on what turned out to be an invalid travel document issued by the Ecuadorian embassy in London [2] (same one that Julian Assange is holed up in).

[1] http://bigstory.ap.org/article/ap-source-nsa-leaker-snowdens...

[2] http://www.theguardian.com/world/2013/jul/02/ecuador-rafael-...