I have just got back from a trip to a time zone 8 hours east with my 8month old. I spent the whole trip dripping milk! It seems ok now I am back in GMT.
I'd stopped leaking at home, and therefore haven't been wearing breast pads for a good month or more, and didn't bring any. Lesson learned- bring breast pads! It was hilarious, massive oversupply the whole week. DD reacted to jet lag by having mammoth feeds all the time (breastfeeding for hours on end at night, and lots in the day), so I must have been producing litres and litres.
Hopefully that's useful info for someone!