I'm starting a sweepstake on when this thread is locked. Five more posts anyone?
Of course, there's always the heated hold [B)].
I think the OP now has a number of replies to consider, and like others I see nothing wrong in UMs travelling, whether their parents are in the front or not. I too went on long trips as a UM when a child, to LAX, South Africa and Chile back then. Since this is a perfectly regular and normal thing to do, I don't see why people should get so agitated and start questioning parental skills.
Some children will love being in the front, most won't mind. So let's not argue about that.
The question in my mind remains whether it is appropriate for the 4 year old to be with its siblings and I think not. Resolve that one, and kingcole probably has the answer that will not create a further spat!
There's a plane at JFK, to fly you back from far away
all those dark and frantic transatlantic miles