Ooh are you going to the west coast ? I did a 10.5 hrs flight to San francisco on my own with DD age 20 mths & the end of Feb this year.
We flew out at 11 am & had a good & reasonably easy flight. If you can sit with your Dd along, then you might be able to get 3 seats together - we got 3 bulk heads on the side of the plane which meant there was plenty of room for her to move around. (I didn't pay for her seat either as she was under 2)
This time I odered a special seat as I had to pay. Again we got 3 seats between us, just behind the bulkhead. I cheekily suggested the man move as he wanted to sleep the whole flight & I was concerned we'd disturb him.
On virgin there is Vtots, which keeps them occupied on & off. I would take little light weight books to read. Some washable felt tip pens & pad (my DD likes little pad) Also take cartons of diluted juice (the heinz ones are good). They quite enjoy the novelty of plane food, but DD didn't really like it & it wasn't the right time so I took a small cool bag with sandwiches & fruit. Take milk for take off & landing. Kept well in the cool bag.
We flew back (this time with DH) on a night flight & it's a nightmare. DD couldn't sleep,e even though she was desperatly tired, I was in a terrible mood because I was tired. I would even consider coming back with a different airline next time we go to avoid the night flight.
Hope this helps.
Don't forget they have the pushchair ready for you when you leave the plane - I didn't know this the first time & walked the (several) miles to customs etc, with Dd ambling slowly behind...this time we were at customs in less than 10 mins.