Jeff,
The USGS supported the collection of the information published on the APSRS CDs. The information has not been updated since around 2000. I have a database dump of the information, but suspect most of the contents would be of little value today.
There is an effort from the American Society of Photogrammetry and Remote Sensing - the similar acronym to APSRS - to maintain an online, keyword searchable inventory of aerial sources. This free service went live spring of 2016 and contains references to several million frames of photography dating from the 1920s onward. The system is not like USGS' Earth Explorer as so many sources do not have frame-based geographics. The ASPRS Aerial Data Catalog is located at
http://dpac.asprs.org/
As part of the volunteer team that developed and maintains this service, feel free to shoot me questions. Also, we are always looking for folks to contribute metadata to further advertise their holdings as the system really is a referral means to discovery sources of aerial photography and to provide the contact information for the sources.
Best,