Great question- I guess we were thinking odds are low for flight to be cancelled. Are trips on BA between AMS-LHR often cancelled or delayed several hours??

I guess we could always take train back to London the morning of the 29th and then get to LHR 3 hours before our departing flight. Our problem is we are flying into LHR on the 21st, have a family event on the 23rd and a sporting event on the 26th in London. So we would either have to do the Amsterdam trip from the 24-26th (which is a lot of running around) or do it at the end of the trip but counting on being able to get from AMS to LHR before our departure time for EWR.

Also, we are not checking any luggage--- just carry ons--- still too risky to do the 4:20 arrival to LHR?