I recently traveled to Philippines,which is 8 hours ahead. I was also wondering and worried how am I going to sort out my basal insulin. My diabetes nurse first told me to either inject bolus throughout my holiday at same time as when I usually inject when I am in UK. That would be 6 am in the morning. I wasn't sure how would that work out.
Other option was to skip injecting my bolus when I am supposed to ( 10 pm UK time) and then cover my insulin needs with fast acting insulin until 10 pm local Philippine time.
She also suggested to check
http://www.voyagemd.com, which is supposed to help with working out your basal and Bolus insulin while traveling.
I would definitely check with your diabetes team which one of those is a good option before your travel.
I worked out that according to voyage Md I would have too much bolus insulin, and I would risk of having hypos during the flight.
I decided not to give full bolus insulin dose (10 pm UK time), I had 20% of my full basal dose, just to have some background insulin, I covered the rest of my insulin needs with more fast acting insulin, I checked my BG regularly, and then I injected the full bolus 10 pm local time. I did have few high BG's but I corrected it with fast acting... I did the same for return travel.
I know this might have been the worst option, not very smart thing to do, but I think it was the best option for me. I didn't want to have hypos during my 22 hour air travel, and I wasn't sure what are my sugars going to be if ever I change my bolus to 6 am.
I hope I gave you an idea which you could discuss with your diabetes team before travel.
good luck