Information for ordering National High Altitude Program imagery is available through multiple government agencies.
The United States Geological Survey (USGS) originally coordinated the program. Their Earth Resources Observation and Science (EROS) Center site, gives background information about the filming, recording, quality, description, and scale of the maps, as well as ordering information and links to download medium resolution images.
In addition to NHAP imagery, the USGS offers other options in aerial and satellite imagery. They note that this symbol indicates the availability of downloadable data at no charge.
The Research Center holds both paper and digital collections of historical Tulsa County aerial maps.