I have a 3 yr old and he has flown more times in his short life span than most adults I know. The first time he flew he was only 4 months old, so we have been there done that. And I always traveled alone because hubby had to work
First you absolutely need to let them know you will have a lap child. When you book there will be a place to mark lap child. You will need to make sure to bring her birth certificate, a copy is best because sometimes they keep it or attach it to the ticket. If you are going to take your car seat you check it with your bags, they will mark it and put it in the luggage compartment, you can wrap it if you want but you do not have to. If you take a stroller you can take it to the gate and they will tag it right there. When you get off the plane they will bring it to you.
NEVER take a bulkhead seat. You have no underseat storage and no seat back pocket in front of you so you can not easily access a bag of fun stuff and food. You also will not have a tray in front for her to play on. NEVER take an exit row or you will have to move.
Going through security can be difficult because you will need to fold your stroller and run it through the belt. You also need to remove your shoes and put all bags into the belt. All of this will have to be done while holding your baby. May I suggest a carrier like a snugli or if you are familiar with a Moby Wrap, Hot Sling, or Mei Tai style. I used this on every trip until he was too heavy, they SAVED my sanity. Instead of using a stroller I would strap him to the front of me and man did it save time and energy. If you are visiting family as I always did then just purchase an umbrella stroller and keep it there so you do not have to worry with it at the airport. If this is not an option then try to get in the security line around other mommies and you can help eachother by holding babies and taking turns.
When it is time to board the plane you need to be sure to be upfront because they will allow you to board first so you have time to get in and get settled before the rest of passengers. Make sure you have a carryon that is small enough for under the seat packed with all your stuff you need to keep her fed, entertained and hydrated. This bag does not need to have diapers, wipes, etc because when you get up to change her you can get it from overhead.
Make sure to pack snacks, small things she can eat or play with. I found having special toys, books, etc that he never saw before was great because he loved having something new. We would buy trip books, soft ones with lots of interaction at first. My son loved to stack things so I would get a few cups from the stewardess when we got on for him to play and stack, or fill with snacks I gave him. Before you have to buckle in and everyone else gets one get things ready. Fill the seat pocket with stuff you want to get to easily like snacks, bottled drink, toys, napkins, etc. I always got an aisle seat because he could hang over into the aisle and see other people and have more room on one side of me. Let her explore the seats and area around where you are setting as much as possible before the seats next to you fill up. I would let him set in the seat next to me until someone actually wanted the seat. Many times people will not take the middle seat next to a baby, unless you have assigned seats. Personally I preferred flying on Southwest because the seats were first come first serve so people were not forced to sit by you. It is great to have that seat free!
When taking off I would definetely recommend giving her a bottle to suck on, it makes her ears pop and will save a lot of screaming. If you are breastfeeding exclusively then I would nurse if you can. Distracting her while taking off helps too so she does not notice the pressure changes so much. If my son had any congestion I would give him some meds to clear him up before we flew, the congestion seemed to make his discomfort much worse.
I liked to fly at nap time so he would sleep most of the way. If this is not possible just make sure to have a lot of activities for her to do. I found that flying with him at that age was much easier than when he started walking. After he started walking it got much much harder. The stewardesses are usually very good about helping out. If you need to go potty just ask and one of them are usually happy to hold her while you go.
Oh yeah, sanitizing wipes. Bring lots. I would use them to wipe down the arm rests, the tray, anything plastic or metal that he would be touching and playing with. Airplanes are like germ central and we used to get sick every single time we flew until I started doing this. And I would keep hand sanitizer with me and put it on his hands on a regular basis.
Sorry this is so long. I have pregnant mommy brain right now so I hope this all makes sense. If there is anything you want to ask feel free to shoot me a message I would be happy to help anyway I can. Really dont worry too much, I have flown alone with my son so many times, and it is not bad at all. There are some people who are a pain, but you will be amazed how many people are willing to help you out.
Good luck and take care.
T.