How to see registration number / tail number?

I am quite new to this site and would like to know how I can see the registration numbers / tail numbers in the history list when I search via Airline Flight tracker. When I search on registration number with private flight tracker, this information is shown for one flight only and I am interested to find out which planes where used for certain flight number during some period of time.
E.g. Which Aircrafts (tail numbers) were used for Cathay Pacific CX270 AMS-HKG since November 1, 2014? … +aware+faq

You can look up airline flights by tail number, but to see tail number for airline flights you need an Enterprise Account.