She wouldn't need a seat , they have extension straps so you hold on your lap. Car seat and pram are normally carried foc but it can vary from one airline to another. No baggage allowance in addition for her though. see [http://easyjet.custhelp.com/app/answers/detail/a_id/5552/~/flying-with-children here]] for Easyjet. Food , buy airside of customs so you don't need to worry but they may scan you again for over 100ml before you board - no limit on how many you can take of 100ml or less so just take extra bottles or use readymade bought in Boots.
I want to take my baby girl to visit some friends in Spain in April. She'll be 4 months old and may sound silly but have no idea what to do about flying with her! Do you just carry them on board and have them in your arms? Or buy a seat and pop her in the car seat on it? Do you have to buy extra luggage for your pram? (It would be easy jet).
And what do you do about taking food in hand luggage? She'll be on more than 100ml by then so I don't know how you'd do food in departure lounge?!