I'm a former Flight Attendant. There are so many misconceptions in this thread I just had to respond. First of all, let me make this clear.
Please NEVER wear your baby for take off and landing. It's dangerous and could kill your child since your body weighs more than theirs.
So let's get that out of the way. Flying with a baby on your lap is unsafe. Strapped to you is even more unsafe. The ONLY way to fly safely is to bring a car seat and have your child strapped in. If you opt to save money and put your baby in your lap, you are chancing it that nothing will go wrong because air travel is safe and statistically, that's likely.
You don't need a mathmatical calculation to prove that an adult weighs more than a child. If the adult, in foward impact falls on the baby, that baby has almost no chance of survival. If they fly from your arms, at least they might land somewhere and survive. We cringed when they explained this in training but it's true. In the Sioux City crash, one little girl landing in the overhead bin and survived. If she had been tied to her parent, it's doubtful...
YOU ARE MORE LIKELY TO SURVIVE THAN DIE IN A CRASH.
Please keep this in mind. Taking the attitude "We're all goners" might actually cause you to give up and not make the effort to get out of the aircraft. Yes, it's happened. You need to be proactive.
Yes, a baby carrier could be a hinderance during an evacution but the main reason it's unsafe is because of forward impact. Many foreign companies have dangerous "belly belts" which are still used because of political reasons. The European Union has tried to stop their use but it gets bogged down with compulsory car seat use and parents will never allow safe flying to be obligatory. They want to save money with babies on their laps. Germany has already banned belly belts and other contraptions on take-off and landing.
Some airlines require "lap babies" to be place on the floor in a prepared emergency landing. Not all. Turbulence, I've never heard of that! The big difference is that turbulence is not forward impact. Less force and a different movement. Not the same.
So if you decide to fly with your child on your lap, just remember to remove him or her for safety's sake. Please don't post that you "got away" with putting your child at risk this way. If you're concerned about safety, buy a seat and bring the car seat on board.
Please, no more threads beretaing airline employees for just doing their jobs and for enforcing rules to help the security of your unsecured children.