It actually says....
Part 1
During the "Previously, on Friends" opening, when the previous episode's kiss between Ross and Rachel was shown, there was some nice instrumental music, guitar and piano. Does anyone know what that was?
Some people have asked what music was used when Rachel left Monica's apartment to go to the airport. But there was no music played at that point.
Part 2
When Ross was at JFK airport and found out that Rachel was a Newark airport, the guitar music was "Yellow Ledbetter" by Pearl Jam. This music continued while the scene changed to Newark airport and showed Rachel boarding at her gate.
Some people have asked what music was used when Ross (now at Newark airport) asked Rachel to stay, but she leaves anyway. There was no music played at that point.
When Rachel came back from the airport and Ross made the comment to himself, "Don't make jokes now," followed by another kiss, the music used was the same studio library music that was used when Ross and Rachel had their first meaningful kiss at the end of episode 2.07.
The guitar music at the end of the show, when everyone left Monica's apartment to get coffee, was "Embryonic Journey" by Jefferson Airplane.