Confused with performances on New Years..?

So I was watching New Years Rockin Bash 2008(something like that), and it showed New York City and some of the famous artists performing there. They showed the Plain White T's that performed "Hey There Deliliah" at New York, I think after the actual New Years. Then, they showed the club at Hollywood, CA and the Plain White T's actually performed there! Im kind of confused on how they got from NYC to Hollywood. It does take about 6 hours on plane to get there..and I know that there is a time difference, but still..it doesn't make sense. Correct me if I'm wrong, but how did they do this?