When I read the title I thought this was going to be someone's attempt at a troll saying that the dragon didn't appear and they got their head chopped off.
Clearly Alduin used slow time shout and, being Dragonborn, you somehow are svcked into the same 'time zone' as Alduin with everyone else practically frozen in time.
Flawless logic, I know.
When this happened to me, the only solution was to reinstall the game.
Have fun with that
Had this happen once. Restarted and business as usual.
This is what I'm thinking. I don't see why one would be forced to reinstall, like the previous member.
I mean, the script for his fly over isn't triggered until you start walking towards the block. There are two saves created for you. One hard save that is created when you jump down from the carriage and the first autosave when you start for the block (trigger) .
The fly over could already be initiated in the autosave, but the hardsave, prior, to the creator should be good. At the worst, like you said... restart the game.
... but not a complete reinstall.
EDIT : Chances are the OP just loaded a previous save or restarted the game , anyway. This thread is just noting the incident.
Why should you be saved? Hokorun do Dov! Like the Nords of today, you have forsaken your savior Alduin. Why should Alduin in return save you?