One of my first posts of 2016 recommended that anyone who generally buys airline gift cards to take advantage of the annual airline credit on the American Express Platinum ($200) or Premier Rewards Gold ($100) card should do so now, rather than taking a chance that American Express kills this option at some point in 2016. While reports on Flyertalk have generally been positive about this ‘trick’ still working, I can confirm firsthand that $100 American Airlines e-gift cards and $50 Delta e-gift cards are working. Not only are they working but American Express is crediting them in record time – only one or two days!

Successful Delta Gift Card Reimbursement
If you want to try it for a different airline, please see the applicable Flyertalk threads below for other airlines.
Update: One note that Ann brought up in the comments – AA will not sell gift cards to NJ residents so you need to chose a different airline if you plan to buy gift cards. So make sure you select your airline with American Express first before buying any gift cards.
United Gift Card Reimbursements
Southwest Gift Card Reimbursements