Could This Be A Clerical Error?

Maybe I'm a little slow, but not intending to be funny. Did the OP pay PSE for their opinion on the items, or did the OP pay for a shipping note with some type of nonsensical number on it? Life is too short … move on.

I'm definitely sailing on. It's just these situations can tend to take the wind out of one's sails sometimes.
Here's one of my favorite quotes…
"The truth is an expensive gift; so don't expect it from cheap people"
-W. Buffet-
Thanks guys for always learning me
Hx

I cannot say for sure since the postmark on the first flight cover is unreadable in the image provided, and there is no indication of the arrival postmark on the back, but the cachet is that for the CAM 18 first flight southbound from Watertown, to Sioux Falls and then to Sioux City, South Dakota on January 17, 1932. The airline with the Post Office contract to fly this mail was United Airlines which had been formed in 1931 with the merger of four smaller struggling airlines: Boeing Air Transport, Pacific Air Transport, Varney Air Lines, and National Air Transport If the postmarkings confirm this, then the Catalog number for the first flight as a first flight would be 18S22 for either destination. There was 191 pounds of mail flown which was a relatively large amount. As a result these particular first flights are not especially rare and the catalog value is listed as $5 which means the selling value would be something like $2 to $5 depending on whether you could find a collector who needed it for their collection..