This image was acquired from
flickr. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
sdasm aviation aeronautics boeing boeing classic classic airstairs united air lines unitedairlines united ual blackandwhite vehicle monochrome aircraft airplane black and white Catalog Manufacturer Boeing Designation Official Nickname Notes Repository San Diego Air and Space Museum Archive Catalog Manufacturer Boeing Designation