Here's what happened:
The Senate first approved an FAA bill on Thursday. The Senate bill, S. 853, is a revenue-related measure, which has to start in the House.
The Senate got around that problem by agreeing that House passage of an identical bill would trigger automatic Senate passage of that House version.
But on Friday, the House approved a version, H.R. 1765, that did not appear to be identical to the Senate bill. The House-passed bill included language saying that no funds can be moved until the secretary of Transportation notifies the House and Senate.
The Senate bill made available to reporters late Thursday night did not include that reporting language, and the version found on congressional websites also does not include this language. However, a Senate aide said that same reporting language was in fact added to the Senate bill at the "last minute."
As a result, the House and Senate view that two bills as identical, the Senate does not have to pass the House version, and the bill will go to the White House for Obama's signature.