I am coming on a cruise ship to Tianjin and staying a night before flying out.

Well, for your case, it is suggested to stay near the Main Railway Station or Tianhuan Coach Station, near which both easy transportation to airport and comfortable accommodation are accessible. If at the former, the Pod Inn and Hi Inn are recommended. Both of them are budget ones. For the latter, Jinjiang Inn and Hanting Express Hotel are within 5-8min walking distance. Let me know if you prefer star hotels.