I apologize if I'm in the wrong area...

I have a 1-page layout that sometimes is two pages, with a single field on the second page. Is there a way to automate not printing page 2 if the field on that page is empty?

Maybe. I don't understand your description that well. Wouldn't it be sufficient to set the single field to slide up, with resizing the enclosing part? 

http://www.filemaker.com/help/13/fmp/en/html/create_layout.9.59.html#1030089

I think that would work if the content on page 1 was dynamic, but it will always take the full page. The second page is like an addendum, which note every record will have.

The second page is like an addendum, which note every record will have.

​If a record does not have a note, and the note field is set to slide up as explained above, then the body part will shrink to a size that fits a single page and a second (empty) page will not be printed.