Having just come back from Florida (I'm pre-diabetic, but manage my diet as if am T2), one problem is food/drink on the plane.
On my flight out in economy (couldn't get a business seat), they had no diet sodas at all, so it was water for the 8+hour flight, as I don't drink tea/coffee.
If you book a diabetic meal, you'll probably get a high-carb one - I tend to take potluck on the standard meal when travelling economy and then bring my own snacks to supplement as required.
On the way back I was in business, so the meal choice was wider and I was OK.
Don't know if you've been to Florida before, but I find it almost impossible to get any fast-ish food other than sugar/grease-burger style offerings in the main touristy areas.
Flight socks sounds like a good idea - and if in economy, make sure you don't have your knees jammed in tightly, affecting circulation.
When it comes to booking seats, you might like to try:
http://seatexpert.com/ and
www.seatguru.com - to make sure you can select a decent seat.