I've started reading David Schiff's Gershwin: Rhapsody in Blue, from 1997. Despite the form of my blog, I can find it hard to slog through a book about a single work. But so far, it's interesting.
He opens by describing how United Airlines pad $300,000 per year to use the music in their advertising, on the plane, and at O'Hare airport. I don't remember this but he mentions how Delta Airlines used a tune from Rakhmaninov's Rhapsody on a Theme of Paganini, maybe due to it's similarities to Gershwin's Russian/American sounds.
He describes how Rhapsody in Blue gets criticized for being just a sequence of tunes. Still:
The fact that the Rhapsody has outlived many works whose compositional credentials have never been questioned raises an interesting aesthetic issue: if a music work continues to be played for three generations after its premiere just how flawed can its form be?