Ah, I'm behind the times. Hope the door didn't hit too hard on the way out. Had a buddy worked for them around the 2004 time frame and described the whole operation with a lot of colorful language.

Anyway, a little googling revealed that "Seaport Airlines" and it's sub-brand Wings of Alaska fly Caravans and PC-12s in commuter operation and therefore must require the ATP with SEL.