Long story, but we are thinking about booking 2 separate flights to Europe. One flight would be a domestic open-jaw - ATL - BOS (Day 1) and JFK - ATL (Day 14). The other would be an international open-jaw - BOS - LON (Day 2) and REY - JFK (Day 14). The international segments would be paid with points and the domestic segments with cash.
My question is, when we arrive in JFK from Reykjavik, do we go thru US customs at that point, since that is the "final" US destination on that particular ticket, or would we go through customs in Atlanta after the JFK-ATL segment on the second ticket? Trying to figure out how long of a "layover" we'd need in JFK to pick the time of the return domestic flight.
(For those who care, this is the rationale behind these flights. Boston has an 8:15am flight to London. Our family despises overnight flights - we never sleep and we can't afford first class. So we want to fly up to Boston the night before, spend night @ airport hotel, take day flight to London next day. For the return portion, there is no direct REY-ATL flight. REY only goes to JFK or Minneapolis. If I book directly from REY-ATL, the flights are either triple the SkyMiles required to be able to get a decent connecting flight via JFK that has a 2-hour connection, or, if I get a reasonably-"priced" SkyMiles flight it sends us through Minneapolis with a 7-hour layover. We are traveling with 2 kids so that is a recipe for torture if we do it that way.)
Thanks for any advice!