I tried asking this question in another post (Infant fares to Caribbean) and got no replies. Maybe this will work.

Has anyone ever flown with an infant in lap from the United States to a foreign destination (in our case Aruba) on Delta? Of course someone has. When did you go and what fare, if any, did you pay for your child.

Delta tells me that I will only have to pay tax for my daughter when we check-in. We bought our adult fares on Expedia.com, which tried to charge us much more than just tax when we included our infant daughter (in lap) in the mix.

Anyone know anything definitive?