I vaguely remember this being posted on AAAC once. Seeing as there is no search function (and I'm lazy), I'll bring it up again. What's your usual plane travel attire? For me...tends to be a cotton navy blazer (or wool in the cooler months), pair of chinos or dark-wash jeans if I'm feeling trendy, and an open-necked shirt. Tie is too restrictive for air travel. In my experience, slipons are a good idea, mostly for ergonomic purposes.