Oddly enough -- I went out and bought "a flight bag" back in the
days when I was a neophyte...I now use it as luggage when I travel
on short trips. And I use my smaller Eagle Creek bag as my flight bag.
It holds

handheld radio
handheld gps
3 pairs of prescription glasses
$5.00 in quarters (little coin purse)
nail file (it's a gender thing...)
emergency whistle, bandaids, chapstick, etc
all the AF/Ds and maps I need

Headset? I've got a beachbag in which I put the 4 headsets if I
need to take them out of the cherokee overnight. Or if it's just
me, I can still put the one headset into the Eagle Creek bag.

It's an older style with pockets on the side (perfect for water
bottle, spare keys, etc), couple of length-wise pockets for
stuff, and an oval zip-open on the top of the bag so it's easy to
get into.

You can find similar at Target, Kmart, etc. Take a sectional with
you to make sure it'll fit in the bag.