K.H.
My daughters first flight was when she was three weeks old. Fortunately, I was staying at a relatives house who had extra space and I was able to put her in the living room for the night. Her second flight, she was 7 months old and we went to Michigan. There we stayed in a motel and of course she had to be in the same room however, there was enough space that I was able to put her a fair distance away from me. Both times, she slept pretty well considering back at home, she had her own room. The third trip, she was about the same age as your daughter now, and there was no exra room for her to sleep except in the same room with me. Again, I had her pack and play with me so she had something familiar of hers. I also made sure on each trip to take something of hers that she slept with at home so she wouldn't feel like she was being ripped from familiar surroundings. (I took her blanket and a stuffed animal that she always had with her.) I don't recall having any trouble at all with her on any of the three trips that I took with her although the third was different since we drove and she didn't like to be in her carseat for so long at a time.