With regard to wine, "flights" are those nasty quarrels people engage in after they've had too many bottles. "Hey, buddy, you wanna flight?"
Wow, that was pretty sad.
I believe a flight refers to a grouping of wines usually tasted / consumed together or as a group. Often times, they have some common, uniting characteristic [e.g. AVA, varietal, etc.], but they can also just be a grouping at a large tasting event that don't seem to correlate that closely.