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Join Date: Apr 2012
Location: Leeds, UK
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No difference whether booking under BA codeshare or AA flight number. The three class A321Ts have often run on the BOS-JFK route, but they operate as two class planes where those in first sit in the 1+1 first cabin but get the normal snack basket service.
If you book that itinerary with domestic first on the BOS-JFK route you will be able to select seats in the front 1+1 cabin.