air fare for infants

About Child fares …?
Hello, I'm a little confused about buying a ticket "cheaptickets.com" I will travel outside U.S.. So basically I'm from New York going abroad, and have a baby of 7 months. From what I read, I learned that children in 2 years later, will only pay 10% of adult fare, if the child in her lap. And if a seat, there would be an air fare of the child. My problem is, How can I pay for the rate of 10% if on CheapTickets purchase only up to the ballot? Could I pay 10% in the airport to check in? or should I pay in the airline? I really have no idea. This is the first time I went out with a baby. Let me know. Thank you!
When going to the CheapTickets site, in the table where you put where you go, dates, etc. says "passengers" and then says in parenthesis (Children or seniors?) If you click on it, you'll get a menu where you can indicate that you want to have a baby "round" of 2 years of age. Air transport is safe so there is little risk that something goes wrong, but as a former flight attendant, I will say that these children are not safe. The recommendation by the AAP, the FAA and other organizations including the AFA Flight Attendant Union is to buy a seat for every family member and bring a car seat on board (as in the car!) As a mother who flies a lot with my three children at the international level, I would say which is much more comfortable and secure in this way. Do the math. Sometimes, when you pay 10% plus taxes, the rate of one child not much more and if you need to check the bags, which will give your child the same premium as an adult. You could end up paying overweight baggage fees and end paying more money with a child in your lap! If you opt for this, in Cheaptickets, they give you the option of marking "boy in the skirt" or "child in the seat "if you are not yet 2 years. Only a few other items, make sure you have the passport of his son. Even if you are unsure of the dates of his or even to go out, get a passport for no delays. Also, when booking, be sure to consult with an agent or directly with airlines to ensure you are getting the best rate. Something you just learned, I want to know before was call the airline. I checked the site and had $ 879 United for a ticket on the days he wanted to travel. I called and was $ 670! From now on, I'll call too! Who have never bought from a consolidator. They have never had best price for us, but check everywhere! Here are my totally non-commercial flight advice; http://flyingwithchildren.blogspot.com If you do not get answers to your questions there, my contact information is at the end. Good luck!