we’ve traveled a lot this year and last with her and a little less than half the time they ask for her birth certificate!
I have never been asked for the birth certificate. Just make sure for your flight you add baby in lap & you should be good to go.
My oldest flew for the first time at the age of 2 and then followed by about 14 domestic flights and they never asked for anything. For all her flight she did have her own paid seat.
Technically, you need a copy of the birth certificate, but they’ve never asked for it when we’ve flown…which is insane to me that someone could just get on a plane with a baby.
They tell you that you need to bring a copy of the birth certificate to the airport but I’ve traveled countless times with my baby over the last year and I’ve never been asked for it. I would say that the only reason I could see you needing it is if your traveling with a lap child and he/she looks around 2 years old so the airline might want verification they’re under 2.