Even if you don't want a bag around your midriff, there are other options. I fly wearing cargo pants. Enough pockets for my phone, wallet, passport and keys without being uncomfortable.
I also always keep my shoes on until at least passing 10,000ft on the way up, and from the descent down. Should the worst happen, I'm not fumbling to get my shoes on or having to run through broken wreckage in socks or bare feet. It makes me cringe when I see folk taking their shoes off before the doors are even closed. Not that I have anything against socks on a plane, just don't think it's a good idea until you're cruising.