We have traveled a great deal with our toddler, just got back from Cancun last week. A couple suggestions....
#1) The airline you travel is important, we picked Frontier this last flight and it was a dream, they are ranked the #1 airlines and for a reason. The seats are much more roomier, all their seats are leather and have the nice head rests that bend so you can use them and the more important thing is they have tv's on the back of each seats.. a life saver with a 22 month old. Our friends all flew American, ranked at the bottom and all they did was have problems, flight delays, etc.. it was a nightmare and with a toddler, can't even imagine.. I love Alaska and who we typically always fly because we have tons of airmiles and you can pick our your own seats online and view if any seats are open in the middle and change them up until the last day. Don't fly American if you help it!!!
#2 ) OK, the biggest advice I can give you is book an aisle and a window for you and your husband. it's worked like magic for us almost always.. We always get the middle seat free and with a 23 month old, this is a true blessing! makes the world of difference, can't imagine a 10 hour flight with my toddler in my lap. If you do end up with someone in the middle, they will always switch to an aisle or window for you and like we had on our flight home. We asked the person who was seated in the middle if they wouldn't mind finding another seat so we can have this one open for our toddler and there were 3 other seats open on the plane and it was not a problem.. most people try to accomodate you when it's for a child!
#3) Dvd players with a good charge, good headphones that will block out the flight noise and that your toddler will keep on. My toddler doesn't like to wear headphones unless we have the right ones and make sure they're not cheap ones because it's hard to hear sometimes over the flight noise. New toys, snacks, books and a couple favorite toys, always good idea as well!! HAVE FUN!!!