Different airline, but my little girl was a week away from 2yo the last time we travelled and she was a lap child, therefore, she flew for free. We are going in May and have a 20 month old who will be going in a carseat and, of course, we will be paying for him. Previous trip, I had no problem with an almost 2yo on my lap once we baorded...No one questioned us about her age or anything. However, just from experience, I am opting to pay to have my youngest (20 months) in his own seat this time around. I was able to find a discount on a fare for a "child under 2 in carseat" on Orbitz. Our full fare was $166/pp and they only charged $97 for the carseat fare. Unless your child is big for his/her size, I don't think you will run into any questioning about age on your return flight. Good luck!