"free for all!" but you do get on in "groups" (assigned first come/first served at the airport with some boarding passes obtained online prior to the flight, but those are not all guaranteed to be in the first group) plus, the elderly, handicapped and those travelling w/small children board first... i have flown w/my children a dozen times and have never had a problem having them sit with me, even when we opted not to pre-board and just took our chances w/the group system...