I now abhor flying commercially because of all the security restrictions (your choice: molestation or radiation) and thus fly only when forced to. That said, I always consider the weather at both the beginning and end of my journey and dress appropriately. I have a carry on bag which has the following:

road maps, professional licenses, FAK, notepad, misc. electronic components for my iphone and notepad, appointment/calendar book, personal logbook, steno pad, 5oz flask (empty), spare cigs, spare ziplock bags, zip ties, $10 roll of quarters, spare glasses, sunglasses, 15ft of cordage, bandannas, bic lighters, magic marker (black), plastic spoon, ink pens, hoodie.

I carry the following on my person:

cigs, bic lighter, ink pen, 2 wallets (ID and credit cards), calendar book, bandanna, comb, sunglasses, iphone, 2 stones (medicinal), appropriate clothing.

My checked luggage (if it was returned while I'm delayed):

Large bag with: 4 sets of normal clothing, seasonal clothing, medicine bag, set of linens/blankets, Shaving kit, FAK w/meds/vitamins, cigarettes, and a teddy bear.

Small bag with E&E kit: KaBar knife, food, VFR charts, 2 Bota bags (empty), metal cup, mess kit/gear, knee braces, bandannas, bic lighters, 25ft of 3/8ths in. line, feador, playing cards, leatherman, SAK, flashlight, credit card survival tool, 4 AA batteries, hat, fire starter, and a photon light/laser. I've got more gear in this bag but this is what comes to mind, impromptu.