We are flying 2 adults 1~ 6 year old and 1~ 1 year old. Buying 3 seats flying with a lap kid. If I understand correctly we can board after A, but before B. THose who get early bird can check in with A, is that right? I am trying to determine if we should use early bird check in? Do we need to go online 24 hour before to check in in all cases? What is the best case for us? If there is someplace that answers these please direct me. 
