Hi there, I've done quite a bit of travelling with baby ( I took Quinn home to Ireland from NZ when he was 3 months old) so I think I can answer most questions
Yes you can take filled bottles through security - they may ask you to taste them though. I was b/feeding Quinn the first time we travelled so didn't take any bottles but the next time we flew home he was about 8 months old and I took 6 bottles filled with sterilised water through security at all airports - Auckland, LA, Heathrow and Dublin and the only place I had to taste the water was in the UK (sorry
). I took his formula through in separate containers and it was all fine.
Nappy cream should also be fine - if possible take the smallest container of it possible in your hand luggage - although anything under 100ml is usually ok.
Snacks for baby are fine, just be aware that some countries have strict policies on not allowing non processed foods, fruit etc into the country - eg New Zealand & Australia has a strict no fruit / vegetable policy but I think within EU you should be fine. If in doubt, you can always ditch anything bubs hasn't eaten on the plane.
Most airlines also can provide special meals for weaning babies/ toddlers. They might not be able to eat everything on the tray but things like fruit, yoghurts and breadrolls can all come in handy!
Feeding either b/feeding or bottle or sucking on a dummy is the best thing for their ears on take off and descent. I'm more in favour of the feeding than dummy sucking as the swallowing seems to really help.
If possible request a bassinet seat against the bulkhead ...although be aware that although you may have requested one, they are usually allocated on the basis of age so younger babies tend to take priority for these. If you can get one - they make the journey so much easier!! Airline will supply blankets etc for the bassinet but I usually bring my own as they're softer.
For older kids eg - 6 months+ it can be so much easier on long journeys if they have their own seat - but be aware that they will have to be seated in a car seat which you must supply and which must adhere to your airlines safety guidelines. Also as the width of some airlines seats can vary it's useful to make sure that your car seat will fit within the airline seat with the arm rests in the lowered position. We bought a car seat that converts into a stroller ( a Godsend for sitting in airline lounges or running through terminals!). It's called the Pod and literally I could wheel Quinn straight onto the plane, down the aisle and then just flick a switch, have the wheels fold back up into the base of the seat and pop his seat into the airline seat and strap it in - I would not be without it!
Also, be aware that most airlines board famillies with young children before general boarding so you have a bit more time to get yourself settled.
Most airlines carry pushchairs free of charge but travel cots etc will only be carried as part of your standard luggage allowance. Most major airlines will allow you to use the pushchair right up to boarding the plane when it will be removed and stowed and then on landing it should be available to you again for use from the airplane door onwards. Some charter airlines may differ so it's worth checking with either the airline or your travel agent before you leave .
Honestly travelling with babies is a breee - it's when they're walking and talking that it gets more difficult
Enjoy your holidays!