You've all heard me rant and rave about the importance of using a carseat on airplanes. I wanted to give you some background information that makes the idea of why a lap child sounds like a good idea, but it isn't really safe.
The FAA believes that the safest place for a child to sit on an airplane is in the child's car seat (or using the Cares harness for a child between 22 and 40 pounds).
http://www.faa.gov/passengers/fly_children/
Why then does the FAA allow lap children under the age of 2 if the FAA believes the child should be in a car seat? Well, here's a Washington answer for you -- lobbying. Airlines have lobbied the FAA to allow children under the age of two to ride as lap children. Why would they do this? The answer is money. When a family adds a child to it, flying becomes more expensive when another seat is needed. So airlines "allow" you to have your child as a lap child for the first two years of the child's life so that you get used to flying with your child rather using another mode of transportation (driving). Their thinking is if you get to do it free for two years, you won't mind the expense when your child is older than two. The airlines know it isn't safe, but they want to keep you as customers. They want you to experience the ease of flying (although flying with a lap child isn't really easy) so that you'll want to continue to do it. In the past few years, airlines have reduced the number of flights and nearly every flight is full. Parents used to be able to get an unoccupied seat for the carseat fairly easily. These days, planes are packed. I fly all the time and I can only recall one flight in the last two months that wasn't completely full.
In severe turbulence, you cannot hold on to your child. The force is just too great. You can't hold your child in a car crash either which is why people use carseats instead of holding the baby on your lap (although you might be surprised by the number of people who come into car seat checks exactly that way). Flying is safer than driving in that you are less likely to be in a crash on a plane than a crash in the car. But turbulence still plays a big role in why you should restrain your child every time you fly. Just as you wouldn't buckle your child in the car seat in a car only sometimes, you should buckle your child in the car seat on a plane.
I really do understand that buying another ticket can be economically out of reach for some families. I will always encourage you to buy a seat and I understand why some people can't. But I will always give you the facts on why it isn't safe and why it is allowed.
I hope some of this information is useful. I want you to have all the facts.
<end of ranting and raving>