The new setup makes it much easier to find what you are looking for. Just by entering what you are looking for, in the search field on the right, you will get there faster and easier.
You can use c/n (for example 22172), s/n (for example 0008; always use 4 digits), registration (for example G-BIKA), airline name, date (for example 01/01/2002).
Below a list with Boeing 757 construction numbers which have been added to the new website. You can click on any of them and you will be redirected to that c/n with a full history of the aircraft.