I had a book returned to me because of the 13 ounce rule and I realize that was my fault for weighing only the book and not the packaging. I just went back to the post office and went in and mailed it and sent the requester a pm letting them know the book was returned to me so it may take a little longer to get to them

what was new to me was a sticker they put on the package-I don't remember the exact wording but the jist of it  was

this package not to be sent by air.

I asked the clerk at the post office why and he said because it was over 13 ounce and I had postage stamps on it.  At that point there was nothing I could do because the postage was accurate but I feel bad for the requester that the book is being slowed down just because I used stamps and it was over 13 ounces.

live and learn.

I don't think that statement is very accurate. Media Mail (whether stamps/counter postage/electronic postage/etc) generally travels by ground, but has been known to sneak onto an airplane sometimes if there is extra room. I think that in the past year USPS has really cut back on flights, because it seems like media mail is traveling slower (more ground/less air) than last summer. 

Using stamps just means you have to take it to the PO. It doesn't affect the speed it travels. Media mail vs First class is what affects the speed. 

I also doubt the accuracy of your mail clerk Karen.  But IIRC the sticker for returned 13 oz. Media Mail has wings on it...no idea why.

The clerk was correct, you are misunderstanding how she explained it.

It CAN NOT fly on an airplane UNTIL it goes back to the sender and it is prosessed properly. not a big deal if it is caught and sent back locally, but say you mail a Package from California to Maine and it gets caught in Maine and sent back. Even if you sent it priority and it was on a plane from California to Maine, it will go from Maine back to California by truck. If you take it to the PO to be processed properly, it will then be allowed back on a plane.

Thanks for your explanations!

The book was originally mailed 9/11

it was returned 9/15

Remailed 9/16

and it was received 9/20

Transaction is complete and the post office had great service!