the other thing i was going to mention is that if it is a night flight and your baby normally sleeps fairly well at night, you won't have any trouble. you may not even have to feed as often as i suggested. you baby will most likely follow his current schedule and therefore not need any feedings except on waking up just before landing.
as for sore nipples.... that will get better with use...you'll get used to it & baby will become more adept at it with practice.
when i took my 2 year old and my 5 week old to canada (36 hours door-to-door, via tokyo, portland, vancouver, kamloops, calgary and finally regina... oh wait, there was a blizzard and we were diverted to saskatoon where we sat on the runway for over 4 hours, unable to disembark because there was no security for us, then finally back to regina) on my own, the one saving grace for me was that i was exclusively breastfeeding. it was SOOOOOO much easier than having to worry about bottles, formula, sterilising etc. i don't even think i took a pump with me....can't remember, that trip is a total blur!