Song ID from Almost Famous
 

What's the instrumental piece done by Nancy Wilson that plays during the scenes between Kate Hudson and Patrick Fugit? Namely, the scene outside of the Sabbath concert ("It's all happening") and near the end in the airport, where he's running as her plane leaves.

I think that's Nancy Wilson's piece... I don't know what the track are... I love that track too.... but I can't found it. :(

Yes, it is Nancy's own composition. She composed all the instrumentals herself in the movie. It's obvious she wrote all the songs for Stillwater too but Cameron Crowe picked all the other rocks songs played during the movie himself.

I'm taking a guess, but is it Lucky Trumble?