Ctlawyer: low cost, low service carriers such as Frontier and Spirit.
I think most of those who fly large families for a little vacation find using British Airways for that a tad expensive. We should thank Herb Kelleher for starting SouthWest and developing a new business model and Press. Carter and Reagan for deregulation, and for fracking industry keeping fuel cheap for allowing masses of Jews to fly to Israel and afford Florida vacations. Just average prices are 2x lower now than in in 1978 + Spirit.
A free tip: you get even lower prices on Spirit if you buy in the airport. Spirit defines part of the ticket as “online sales tax”. With that, they do not pay other taxes on top of this tax. If you pay at the airport, you do not pay it, of course. So, if you have bli ayn hara a large family, hop in the car, go two hours before Spirit has a flight (when they asre open but no lines), have one person wait in the car. If you ask nicely, they can even assign your seats for free.