Look at this in the best possible light. It's very easy when you have diabetes to become stuck in your routine, and get anxious about disruption. Use this trip as a great opportunity to demonstrate to yourself that you can do what you like with diabetes.
I'm much like you in that I'm 'don't ask, don't tell'. You don't pipe up at work and tell everyone you've got asthma or hayfever or arthritis or whatever, therefore I don't really feel the need to do so for diabetes. This is because as long as you manage your diabetes, it's no more of a problem than any other condition.
As for the practicalities....
Get a doctor's note explaining you need all your needles, insulin etc. to go with you in your hand luggage. You probably won't need this but it's always handy.Take enough supplies for 3 weeks plus an additional 50%, you never know.
Put all your diabetes supplies in your hand luggage. Insulin will freeze in the hold. Plus, given how luggage in the hold can go missing, I can't imagine a worse situation than landing in Miami and finding my Novorapid is currently circulating a baggage carousel in Murmansk. There is some debate about whether your medical supplies don't count towards your hand luggage amount. My approach is to not be a pain at the airport and just put everything all in the same bag and stick to the weight limits.
You'll probably get stopped when your bag goes through the x-ray as the security staff get all excited when they see liquids in your bag, only to become incredibly bored and disappointed to find it's only insulin. Don't worry about keeping insulin cold for the flight but you'll want to put unopened carts in the fridge when you land.
Also, expect to find your BGs get screwed up a bit on a flight. On every flight I go on, I always screw up the carb estimating on the meals and flying seems to just make my BGs go up anyway, presumably from the stress. Deal with it as best you can but don't worry too much about it. Don't order a 'diabetic' meal on the plain unless you consider cardboard to be an essential part of a balanced diet. Also, 'diabetic' usually means 'a big piece of fruit instead of a small cake' which is largely useless in terms of diabetes control difference.
Assuming you're on MDI....you'll also need to plan seriously regarding your basal insulin. If you're flying for 12 hours, you are probably going to encounter a significant time difference (unless you're going to South Africa). What you'll need to do is start adjusting your basal timing by two hour intervals - depending on where you're going, you'll either need to do it two hours earlier or two hours later. Keep moving this every day as appropriate. You can then move your basal to be at a more convenient time for the time difference without compromising on your control.
For example, say I'm going to Thailand (6 hours ahead) and I do my basal at 8pm. That's 2am in Thailand, a bit impractical. So before I fly, I'll move it back to 6pm (12am), then 4pm (10pm). Then when I land in Thailand I can then do my next one at 8pm Thai time (2pm UK) and it's all good. As another note, pick a time zone and stick to it for the entire flight if you need to inject a basal while actually flying. Makes things much easier. And obviously, reverse the process for your flight back.