It was probably Mr. Blue Sky by Electric Light Orchestra. I didn't see LAX, but I remember that song was in the Eternal Sunshine trailer. If that isn't the one then it might also be Light and Day (Reach for the Sun) by The Polyphonic Spree, but I would bet that Mr. Blue Sky is the song you mean.


> What is the song from the trailer of Eternal sunshine of a spotless mind? It was also at the end of LAX on NBC on Monday night.
> It's not the Shining by Badly Drawn Boy but another film.