I think there is some confusion, I'll try to pull my point together here.
A new unused complete ticket had a cover page with a box where the name goes
(shown in image with 2 tickets), it lines up with the name box on the red carbon layer. The ticket agent usually opens the cover and fills out the info on the first page to be imprinted on the red carbon layer. The Mitchell and Cooper ticket images only show the red carbon layer, not the top layer. In some cases, maybe very rare, the name box on the cover is filled out by the customer, you can see in the image where it is filled out, lines up with the name area and you can see the red carbon layer underneath. A customer wouldn't fill out the inside of the ticket but they might fill in the name box on the cover.
I am NOT claiming that the hijacker wrote the name, but exploring the possibility, hopefully to eliminate it.
In your other post, the "cover" photo was named "nwaticket1968.JPG" which leads me to believe the tickets and covers you posted were used in 1968.
I know for a fact that Mitchell's ticket was in an envelope because I took it out of the plastic bag that his mother kept it in, touched it, looked at it, set it on a chair and took a photo of it.
Can you be 100% positive that these "covers" were used in 1971?
The tickets do come with envelopes, but the layers get separated, I don't know where the covers end up going, that is the key. If Mitchell said he didn't write anything, I believe him. However, Colbert claimed that he spoke to a ticket agent that said sometimes they do have the customer fill out the name. If that is true, (like the pic of the ticket I showed) then the name would be filled out in that box on the cover of an unopened ticket.
Mitchell's ticket was only part, not all layers.
I can't confirm NW Orient tickets in Portland in 1971 had that box on the cover, but every ticket I found in the era had that box, most had no name in that cover box. So, I assume it is optional. the name can be written on the front outside cover of the ticket or on the inside first page and show in the red carbon. An agent may ask the customer to fill their name in the box, then take it, open to first page and fill in the rest.
If the cover "name box" on Cooper's ticket was blank then he didn't sign it. 100%. The FBI must have the other layers of that ticket.
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