I realize this thread is older but came across it when searching for pineapple checking info and thought I'd update it. Came back from OGG on AS to SJC and checked a box of pineapples for free. I got them from "Mr. Pineapple," which is above the Shell station near the airport. I don't know if it was because he packaged them up and had the ag stickers on the box already, but the baggage agent didn't even blink. Mr. Pineapple said it was a 'support Maui agriculture' thing, and since he's been in business for over ten years I guess I believe him. But the point is you should be able to check a box of pineapples for free with any airline back to the mainland.