Actually....the pockets in a Scottie vest are quite large.

In my Scottie vest I have carried alll at once: An ipad mini (im sure I could Do it a my 10.8 ipad pro also) a 14 inch laptop. A bottle of water. A G37x bridge camera. A 10,000 mah battery, full sized Sony head over ear headphones, cables, snacks, chap stick, cleaning cloth, glasses, and tissue.

No problem at all. I treated my vest till it's 100% water proof so it doubles as a rain coat (which gives it a second purpose during the trip) and the Tropophormer has zip off sleeves which extends its usable life to 3 full seasons.

If its a long enough flight I've successfully situated everything in the seat back and the Scottie folds inside itself to make a handy pillow to put against the bulkhead and lean on, giving it a third use.

The only con is you are definitely going to look ridiculous doing this. However you do look much less ridiculous than you look wearing the aforementioned true photo vest so there is that....(frankly I've tried it and it isn't for me unless im desperate).

Then again...i've grown tired of lugging luggage through airports and am considering going back to checking at least 1 bag and carrying a much lighter carry on so what do i know?

TSA however could not care less about it one way or another in my experience.

For a belt I always travel with a sturdy paracord belt that way I have ample paracord on me if heaven forbid an emergency were to happen there are lots of very helpful uses of paracord rope.