I get them every year from activity on my Aadvantage credit card.
Have another one expiring end of Sept and they already sent me 2 new ones (have 2 cards) for this year.
I rarely pay for airfare but use miles instead so I usually give these away to family as I cannot use them to taxes on the award travel.
Pretty sure all you have to do is put in the voucher code to use it but if it requires doing it through my account it wouldn't work
for anyone. Worth a shot if someone was planning to pull the trigger and buy airfare today.