Holiday with an 11 month old

Morning ☺️ Wondering if anyone can help me. We’re planning on going abroad and flying with Jet2 within the next couple of weeks.. Can anyone answer some questions… • stroller/buggy is this considered part of your luggage allowance • can anyone recommend a reasonably priced buggy that meets their travel standards • transfers - do we have to contact them to request a car seat? • milk - I’ve seen some people have taken tubs of formula. Did they find this easier than sourcing cows milk? • did you take a bottom sheet for the cot or do most places provide them? Any other hints or tips welcome 🙏🏼