I planned to have Piper 4308M from 0900 to 1300 for my long solo cross country. As I pulled into the parking lot, my instructor’s pickup was already there. I had spoken to him about arriving early to pre-flight the Piper. I had been obsessing about the weather leading up to this flight and repeatedly looked at each airport along my route. I was worried about high winds in the days prior to my flight.
I called the tower and instead of the usual Alpha to 29, I was advised to turn right on Alpha, left on Charlie and back-taxi on 29 to Echo. I stumbled through my read-back to the tower and cleared the taxiway prior to proceeding. I then noticed an airliner had been pushed back onto taxiway Alpha. The tower then called the airliner and asked, “Who cleared you to taxi?” There was no response from the airliner.