I have flown twice with my daughter who is now 16 months old. The first time she was 11 months.. It takes a lot of planning and preparation- and Ihad my husband to help on the first trip and my husband and her nanny with us on the second trip. Going it alone would be tougher.
I took two bottles of prepared formula with us. And two 8 oz cans of ready to feed formula. I would suggest buying some formual in small cans that you can bring- the formula will not spoil in the can- and you have to be ready for any delays...there is no place to buy formula at the airport.
I basicly figured out the amount of food and diapers that we would need for the flight and the waiting time at the airport -and then I doubled that amount.. that is what I packed for carryon... You need to have extra supplies for any delays.
You can buy diapers and formula once youget to your destimation- so you wont have too much to carry. WE checked her carseat at the front... but kept the stroller and gate checked the stroller. So we had the stroller until the very last minute gettin on the plane.
TSA may want to see the formula -sometimes they want you to bring it out of your bag and sometimes they dont... I wouldnt bring any creams or ointments in your carry on- put that in your checked bag.
I picked our flight times around my daughters sleep schedule.. I made sure that our flight left after she was normally up for the day- and that our return flight in the afternoon got us home in time for her normal bedtime. But my daughter is a bed sleeper... She does not like to sleep in carseats or stroller or be held to sleep- she likes to sleep in her bed. She did fall asleep on the plane on each trip and got a good 1 hour nap while we were flying- once she woke up when we were starting to descend- and I think it was the pressure in her ears that woke her.
do your best to keep your son on his normal schedule. a tired baby is a cranky baby..
Ps.. there is no such thing as a vacation with a baby. you will be taking your son with you- so all of his care with still be there while you are traveling... and it is harder to care for him cause you dont have all of the stuff you do at home..