A family friend brought me some United stationary from when he flew somewhere in Asia in the late 90s. I think they still gave it out to first class passengers. The last airline playing cards I have are from Southwest, from around 1999-2000 or so.
On a sidenote, I actually paid $20 for a pack of unopened Continental cards from the late 70's or early 80's. Rip off? Maybe. But at least they're mine now!
(To those in the LA
area, if you ever go to Laguna Beach I highly reccomend a stop at a store called Aviation Arts...it's mostly military aviation stuff, but at any given time they usually have a bunch of random airline models and artifacts such as cards, magazine advertisements, timetables, swizzlesticks, etc.)
Every flight counts.