The other interesting restriction on the Delta SkyMiles Platinum Optima card companion certificate is that you have to purchase the ticket using such a credit card.... I was mailed mine after I had canceled my card (having collected the bountiful bonuses available in the first year, including the spiffy 50,000 miles matching bonus), not realizing that I was going to get mailed this companion certificate on my first card anniversary. Makes it a bit harder to use....