Pun more or less intended, since film buffs consider that the movie that launched the genre is Airport in 1970. Those who watch it now may wonder why it qualifies as a disaster movie at all, since most of the focus is on the characters' love lives and (more interestingly) the technical minutiae of running a large airport; but it would appear that it gave Hollywood the idea of making more films about large numbers of people getting stuck in catastrophic situations (The Poseidon Adventure, The Towering Inferno, etc.). The genre went into hiatus in the 1980s and early 1990s but came back with a vengeance once CGI effects had matured enough.
So what if Airport is never made?
So what if Airport is never made?