how can i go to the Xian Xianyang airport from downtown?

I'd like to travel in downtown on the last day at the city before I take the flight back at the same day (22.50 departure time). And my hotel is the different way to the airport.

1. Should I go to leave my luggage at Xian Railway station in the morning and go to pick it and go to the airport in the evening? If it's worth, how can i go to the airport from Xian Railway Station?

2. Is there any locker in downtown?

thank you in advance.
Kanittha