if you wanted to search airliners.net without actually going there and using their search function, you could always type into a google search (no brackets):

<american 757 business site:www.airliners.net>
<757-223 business site:www.airliners.net>

can swap "business" for "first" as well to change/get more results.

i use this format for all kinds of searches when it's a specific website i want to search and their search function pulls up too few or too many results or irrelevant results.