Does sound an awful lot like a best-of collection of SW FA announcements.

For what it's worth, Alaska doesn't seem to have a flight 438 to SF or elsewhere. Of course this has been going around for a few months, so maybe it's a discontinued flight.

A few google searches shows that there are different version of this going around, with slight differences. One has the flight being specifically from Seattle, although that's on a Seattle radio station site, so it could be embelishment by a listener to make sure they posted it.

cnk