For many years now I have used the FOIA, only recently have I return to using this Act.
There are many problems with the FOIA, firstly is trying to understand the complex nature of the Agency you are trying to obtain records from, especially if they are compartmented in their structure, one hand does not know what the other is doing, it seems. Records usually get shifted about according to one regulation or instruction, so trying to track them down is a task in itself. It is like trying to chase a shadow, once you think you have a light on the documents they disappear.
And recently, I filed a FOIA request to the USAF for "Records, photographs, and other imagery pertaining to unidentified flying objects and other aerial phenomena which were filed or obtained under DOD 5040.6-M-1 "Decision Logic Table Instructions For Recording And Handing Visual Information Material" section C5.21 "UFO and Other Aerial Phenomena Imagery." This document is dated October 2002. Since these instructions exist, I can safety assume records existed before the creation of this document, and this fact instigated the creation of these instructions. This document is currently active." It took approximately two months for a final response, and it was "no records".
I have filed a request to the DOD as well. It seems anything mentioning the term UFO is sensitive, since no records always seem to be the response regardless of the UFO incidents that have occurred in the US, unless of course NORAD is the OPR for these matters, but I believe they are only one of many involved in these matters. That is if the term UFO is used to described these events.