You are assuming that the glidepath is the only reference for an aircraft on a CAT III approach. But CAT III (and II) also require a radar altimeter, which would foil a Die Hard II scheme.
In addition, the aircraft would not be at the proper height for its location along the approach.
But it was a fun movie to watch, even if extremely unrealistic.
In North America, there is ONE refinery still producing it. And they pretty much only run a batch once a year - an entire day's production is sufficient for an entire year. Something like all the avgas used in a year is equal to all the regular gas used by cars in a day.
Don't suppose you have a reference for that assertion do you? There are several refineries in USA that make avgas, and production is much larger than a day.
In 2009 there were 10 refineries making avgas, this article indicates there "seven or eight" in 2011.
Check out this table , courtesy of the Energy Information Administration, for a summary of regions where avgas is produced.