True FT elite!
The problem then was that the pass had to be activated within 15 days of landing and then was valid for 30 days, so you lost use of the second pass
Plus, you were only allowed one such Visit USA pass per person.
Oh, the good old days. Northwest had an even better variation. They had a confirmed reservation unlimited flying pass at one time. It costs more than the DL pass, but not that much more. I remember using that one in 1986/1987. They even extended the expiration date of the pass for me (very easy to do with the way the pass was issued).