Yes definitely confirm a child's meal. We flew KLM last time and the meal was very interesting the children didn't know quite what to make of it. My brother and family came to visit and flew on Virgin and by all accounts they had great provision for children. I was impressed. I think the Asian airlines are best though - dh flew Cathay Pacific across to Vancouver, and had an excellent Chinese meal. Sorry - I digress I would take extra supplies on a long distance flight with children just in case.
Last April we flew to Orlando with BA...didn't have the child mmeal on the way over as you canot book them when online check in,the deadline had already passed (very odd) but it was nuggets I think,mine were actually OK with the casserole or fish adult meal.On the way back did have childrens meal for ds3 ,it was ghstly ;grey sausages really foul looking ,them he was given cereal at midnight befire we landed ,the adults got a am role which would have been better for him!
Where are you flying from - Gatwick or Heathrow?. Food choices in the departure lounges at these places is better these days.
I'd order the child's meal for travel but get something for him to eat also before boarding. Also take some foodstuffs he likes along too - do not rely on them to fully provide. I've been on flights where they did not have enough children's meals to go around!.
You also need to bear in mind that childrens' meals are served not all that long before the adults meals are served.
definitely order child meal in advance (although on occasions we've ordered and they haven't had them!) we therefore always feed first in departure lounge and take some sandwiches/crisps etc too. No problems with taking food although they are still really anal about liquids but you can buy them in the departure lounge. we flew BA in the summer to Orlando and they did not provide a meal for our DD as she was under 2! This was despite the fact we were business class and had to pay around £500 just for her to sit on our laps! Tight gits!
T5 is supposed to have some good restaurants there. If you do a google search you should find a list of restaurants in T5.
You can take food (and drink) on the aircraft - but do leave behind any extra ham rolls for disposal when you disembark (you must do this also with any fruit). This is because US customs do not permit these items to be brought in by passengers.
Don't forget the passports!. Ensure also that all required immigration and customs form is filled in well ahead of time before arrival into the US (you will need to also complete and sign an immigration form for your son).
Your son won't be fingerprinted and photographed but all adults will be.
ask for the visa waiver forms at checkout and they may have them. If not, get them on the plane and complete them before you land. You should complete one green form per person in the party (adults sign on kids behalf) and one white one for the whole group. Make sure there are no mistakes as immigration can be really anal and make you do it again (and go to the back of the queue!) if there is a small mistake.
Visa waiver rules changing from 1st Jan, see http://www.britishairways.com/travel/usawaiver/public/en_gb
You just fill in the same questions you'd get on the green form online and get an instant confirmation (assuming you're not a commie!). We've done this for our trip to LA in Feb. Apparently it's voluntary to the end of the year but compulsory in new year, should mean the end of the paper waiver, but they may keep both running in conjuction for a while longer.