Relevant in what way? It’s a work of fiction.
Just saw on the wiki:
"The book presents an overview of the operations of a major commercial airport, much of which is still applicable over 40 years later. Several major and minor characters appear, illustrating the vast complexity of the airport and its operations, including customs officers, lawyers, airport police, doctors, clerks, snow clearers, et al."
Seems like it's still relevant :)
https://en.wikipedia.org/wiki/Airport_(novel)