Stuff like aircraft plants, ball bearing factories, oil refineries, and basic airfield buildings.
Google is not letting you down, your own skildz to use it is :)
Anyways, I have used often HO (1/87) scale raildroad pages and magazines (and other modeling magazines) as a source for industrial buildings, and airfield stuff too can be found although it is tougher - especially german airfield stuff is almost impossible to find... here's few links for my own search adventures:
http://www.controltowers.co.uk/
http://www.discounttrainsonline.com/Faller-Building-Airfield-Control-Tower/item272-144047.html
http://www.tri-ang.co.uk/Airfix/ControlTower.htm
http://www.tomtom-net.de/resources/cardmodel/hangar/hangar_f.htm
http://www.gatewaynmra.org/mhslayout/mhsbuildings1.htm
http://images.google.fi/images?svnum=10&hl=fi&lr=&q=nissen+hut
...And so. It's all about the words you use for searches, net is full of information but sometimes you have to use other than "the obvious" words to find them.
Also few books from your local library would help, even if you don't go as far as I have gone - I have several books about airfield architecture and equipment, and have bought few plastic models too for reference. And yes, I strongly deny that I have anything wwII related modeling going on if you ask :P
I can post few pics and a link to a free aircraft hangar and simple modular barracks I made year ago for my own purposes (supplied untextured & unmapped, but hey, they are free if anyone wants them).