Xian Aiport Bus to Alley Youth Hostel - flight arrival 11.40pm

Well, according to your arrival time, you can take shuttle bus to get to Xishaomen Airport Business Hotel first. The operating hours are until the arrival of the last flight. So you can catch that.
It takes around an hour. The ticket fare is CNY 25 per person.
After arriving, take a taxi to the hotel directly. The cab fare is about CNY 12 at night.