You are excited because you have a perfect plan for a trip with your baby. It will be your first trip and you have to have everything to make it a great memory.
The first thing you have to do is to discuss it with your pediatrician and find out if your baby is in good condition to be able to go out and if he has any recommendations to make. A very good tip, is to ask him for an emergency kit prescription, so you can buy the basic medicines necessary in case of a mishap. In some countries they do not give you medicine so easily or without a prescription, so it's better to have everything ready in case it's needed.
Bring enough clothes, because although you may buy baby clothes on the trip, in theory you should wash it before putting it on your baby. Two changes of clothes per day is a good parameter. I always carry a full pack of diapers. At first it looks a bit burdensome, but at the end of the trip, it is an extra space in the suitcase.
If you breastfeed your baby, you are in heaven: you do not need to bring feeding bottles! But, with 2-4 bottles, a bottle washer brush (#DrBrown's) and a little detergent for emergencies, you are all set. They sell sterilizing sachets of #medela that you can use in a microwave to sterilize the bottles.
For the plane, it is important that at the time of takeoff and landing, you breastfeed or bottle-feed the baby to avoid ear pain. Never go on vacation without your stroller. Maybe your husband would tell you that it is very cumbersome or that you won't use it, but you will see how the whole trip you will remind him how good it was to take it. You deliver the stroller at the door of the plane, so it is of great help when walking in the airport while the flight departs. In addition, it is the most comfortable thing in the world, since it becomes your shopping cart throughout the trip. When your husband no longer wants to carry something and wants to put it in "your stroller", it is the best moment to remind him that he did not want to take a stroller, haha.
If your baby is a little older, always carry some toys so you can keep him entertained, you will not want to feel the intimidating looks of other less empathic passengers. The diaper bag must be always close to you. Do not let your husband put it in the compartment above, since you need to be taking things out of the diaper bag and it's a mess. Take a thousand photos of your baby and enjoy the trip!
