Hi A.,
I have always traveled with my kids when they were different ages. I traveled by myself as well, especially when I flew to meet my husband somewhere (he would go on a business trip). It is always somewhat stressful to travel with a baby, because you do worry about how they will be. I always found that my baby did well if I nursed him on the flight when he was ready to. When you notice that your ears are popping and you need to swallow, that is a good time to feed the baby. Swallowing will help their ears adjust. Sometimes babies cry during that time because they don't know what it is. Most people don't choose to sit near someone with a baby if they don't like babies. Most people do like to look at and be near a baby. Also, someone who has kids or a baby at home may sit near you, because they know what you are going through. You can choose a window seat, so you can look out the window while nursing. Or, you can choose an aisle seat, so you could get up and walk with the baby if you needed to. I always found that my baby was just happy to be with me, and once we settled in to the flight, he would usually fall asleep.
I don't know that the flight attendant can heat up the bottle of milk. She can't use the microwave because it destroys the immune properties. I have heard of something, although I haven't seen it recently, it's like a cold pack that goes around the bottle (like a wrap) and you do something to it, and it starts to warm up. I met someone who had one, but I haven't heard about them in a while. Maybe someone else will know about it?......
Best of luck, I'm sure you will do fine.....keep up the good work with breastfeeding!