Here are some tips on air travel with kids.  Do note that situations vary from airline to airline, from aircraft to aircraft.  When in doubt, please check with your airline.

For more information on air travel with kids, there are a lot of sites on the internet.  As a start, do check out the following websites :

Long Distance Airplane Travel with Babies

Flying with Kids

(a) Choice of seat

Most advice you find will recommend that you take the bulkhead seats.  These are the very first row of a particular section of the aircraft, with the partition in front of you.  The reasons for recommending bulkhead seats are because  there is more space/leg room and the aircraft bassinet can only be attached to the partition.  I am not very certain about the price of the ticket (it varies from airline to airline) but if you have to choose between paying cheaper for infant tickets that comes with bassinet use, or a slightly more expensive child ticket that lets the child has a seat of his own, choose the latter.  You may be glad for the extra seat space.  Unless, you are travelling with young infant and need the bassinet, of course.

Do note that the bassinets are not very big and if you are travelling with a toddler, you may not be able to use the bassinet.  The other downside is that the armrest for bulkhead seats cannot be raised.  I find this very inconvenient. Firstly, your kid cannot sprawl across seats to sleep.  Secondly, it is difficult to breastfeed a bigger kid if the armrest cannot be raised.

Another issue with bulkhead seats is that for some aircrafts/airlines, the movie screen is right above the bassinet and the lights can be very disturbing for your baby.  Some airlines will also require you to bring your baby out of the bassinet and strap him with you while the seat belt sign is on.  This will be a source of irritation to you and disturbance to your baby.

(b) Meals

If your child is already taking solids, you can ask for 'post-weaning meals' when you buy your tickets.  These are meals consisting mainly of mushy stuff that older babies eat.  However, if you have other special dietary concerns, e.g. allergies, do let the airline know and see if they can accommodate your requirements, or be prepared to bring your own food.  The airline usually also has commercial baby food in jars.