03:00 is a strange time to start. Lets think about why they are starting so early.
1. you want thousands of drunken NY’ers exiting their chi-chi bars after a night of drinking participating in the start line event.
This probably isn’t the reason.2. They have to catch a very early flight. Much more likely.
Now - which flight?
Assume the flight is before 10:00 - otherwise you could start the race later in the day.
TPTB also like to be able to have flight choices for the 1st leg. i.e. the teams that finish the start line challenge 1st get the 1st flight etc… and they like to have an early flight to get Phil there first.
There are 3 international airports within reasonable transit/taxi/driving: LGA (Laguardia), JFK (John F Kennedy), EWR (Newark)
LGA - international “bunched” flights excluding Canada from 06:00 to 10:00:nothing
JFK - international “bunched” flights excluding Canada from 06:00 to 10:00:London BA 180 British Airways 07:15 18:55
London VS 26 Virgin Atlantic 07:40 19:40
London BA 178 British Airways 08:15 20:05
EWR - international flights excluding Canada from 06:00 to 10:00:Hmmm, this is interesting
London VS 18 Virgin Atlantic 07:15 18:54
London UA 922 United Airlines 09:00 21:20
From my analysis - I’m going to bet heavily on London being either the first leg or a connection to another flight.
Send Phil off on BA180 at 07:15 and let the teams travel on VS76 or BA178 or even UA922 from EWR

It could be fun if the teams aren't told which airport to go to...
Any NY'er (who aren't drunk) willing to hang out at JFK or EWR Saturday morning?