I just watched the very entaining video 'The Shovel Bum's Lot' however the 
transact and shovel testing method described to find sites had me wondering 
how much American archaeologists used aerial photograph analysis to find 
sites, particularly historic sites?

I work in Western Australia and the combination of big country and 
inadequent pay for the job had me running to aerials fairly promptly. I use 
enlarged aerial photographs to pindown promising search areas, find actual 
features to investigate and as a mapping tool so that I only physically 
measure within discreet areas. Of course aerials are not much use in forests 
so may not be much use in the wilds of Arkansas.

I also find they can be useful in an urban context for finding sites in 
backyards and areas now paved but open in the1840/1950s.