I tried to reply to the prior thread on this topic : Apparent Unauthorized Use Of My Pix (by jelpee May 26 2012 in Aviation Photography) but even though it has not been locked, there was no facility for me to reply. My apolgies in advance for starting a whole new thread on this.
I wanted to provide an update on this issue: At last report, I had contacted Delta and sent them an invoice for a usage fee. To Delta's credit, they paid me the requested fee for which in return I granted them permission retroactively for their use of the image.
I was pleasantly surprised!
Thanks to all who provided guidance and counsel on this topic.
[Edited 2012-07-17 19:08:17]