We went from Manchester to Brisbane, with changes at London and an hour or 2 in Dubai with our 10 month old. We had a seat booked for her so had a row to ourselves. I took plenty of toys and snacks. Me and my partner sat at opposite ends so she could stand in the footwell and I put my feet up so she had a small space to wander up and down. Other passengers were lovely and talked to her as she to is chilled so out of the whole 26+ hours in the air we had one over tired breakdown!! As far as jet lag, she was fine like the previous comment on the flight she just slept when she wanted so didn't have trouble adjusting when we arrived. I was also breastfeeding so that was a life saver. Oh and prepare for no sleep on the flight!! We survived I'm sure you'll be fine!!x