i just travelled to canada with my 1 year old by myself, 27 hour flight. i'd suggest ringing the airline you're flying with and asking for a bassinette so that the baby has somewhere to sleep, although if there are babies younger they will go to them first and some planes aren't fittes with bassinettes, also feed your baby for take off and landing as the sucking helps equalised the pressure in their ears. since it's a 3 hour flight they more than likely will sleep for most of it so you shouldn't have a problem, just take a few toys to amuse them with.

my baby sis had some trouble on descent, her ears wouldn't pop, she kept grabbing at her ears and wining. if this happens, its best to let them cry a bit, as it usually equalises the pressure, but if it doesn't then just take her to a chemist and get their advice :)

talk to your dr and see if there is anything you can give her to help her sleep through the trip.

if not like the others have said keep bottles ready for her, toys ect to keep her occupied. also try and keep her awake till ur on the plane that way she can sleep whilst flying.  im flying to new zealand next yr (my son will be 1 then) so im in the same boat im gonna need tips to help keep him occupied whilst flying. 

good luck in finding a easy and stress free way of flying and have a good trip.

From experience make sure they are tired. Bottles for takeoff and landing or a snack to munch and suck on (Muesli bar) Also in case they do cry alot take her fav toy. Also maybe something that calms you. Rescue remedy, chamomile tea. What ever works for you.

 If she's awake on the way up and way down try to encourage her to feed.

Plus, in your bag that is at your feet, just stash a mini pack of wipes and a couple of nappies, so you don't have to go rummaging through big bags and getting bags down from overhead lockers should you need to change her.

It's easy. Pick the nearest flight after her normal bed time, let her go off to sleep in the car on the way to the airport, pram to the check in counter, they will give you an airport stroller so you'll have to swap her over there into their stroller; from there into the plane. Have a couple of bottles and on hand and if she stirs taking off or landing, get her to suck. Do not make any sort of fuss or drama about the trip, make sure you stay relaxed and cheerful....and....

Voila

Happy flying!