I travelled with my twins from South Africa to Portugal when they were three months. The flight from South Africa to Frankfurt Germany was a night flight, so we asked for baby cots (see first picture) when we booked the tickets. However, this meant OH and I couldn’t sit next to each other but rather on opposite ends of the same row because only one cot can be attached on each aisle.
We than took a three hour flight from Frankfurt to Oporto, Portugal. During that flight, the babies had to sit on our lap (2nd pic) – once again, you and you OH will not be allowed to sit next to each other because of the air masks in the event of emergency landing (my OH sat with Clarissa in the seat in front of mine and Gabriel’s).
During both flights, we were allowed to take our stroller in the plane – it is a three piece with detachable carseats. At the door of the plan we simply folded it and left it out for the air hostesses to pack it away. Since we had our own car seats, that also meant when he hired a car we didn’t have to pay for additional car seats. If your buggy doesn’t have detachable car seats, go with the buggy alone (it is an absolute lifesaver on holiday when with twins – especially at the airport amidst all the chaos) to avoid excess luggage and hire car seats if you intend to rent a car. When organizing for transfer from the airport to the hotel make sure to mention that you will be traveling with twin babies as it could be required for them to sit in car seats. Oh yes, and take at least one sling with you if you can. My OH carried the one baby in the sling so that his hands were free to fold the buggy, carry the luggage and what not.
As for sterilising… we didn’t need to at all despite traveling for over 17 hours with twins. We simply took lots of empty and sterilised bottles in our hand luggage and measured formula in those formula carrying containers. All airports have changing rooms that also have taps with safe drinking water for babies. So anytime we needed to make bottles, we simply adjusted the water temperature on the taps, poured it in bottles, added formula and viola! The truth is, one of our flights was slightly delayed and we simply wouldn't have had time at the airport to sterilise bottles before catching a connecting flight. Once at the hotel you can use sterilising tablets for dirty bottles.
Remember to keep all you baby liquids together to make thing seasier at the security checkpoint. Although they are strict at controls, things are different when you have babies. You can go past control with full bottles of milk as long as you drink a little of it infront of security to prove that the milk is not chemicals (only if asked) and you can carry baby meds like panado, bum cream and so forth.
Most of what I wrote is useless info if you are not using an overnight flight or connecting flight, but since you didn't say where you are going throught I would indulge myself. Anywa, if you have any questions, you can PM me and I’ll gladly help where I can. I’ve been through it, survived and got the super mummy badge.