Originally Posted by
Often1
3. However, do not presume that there will be availability on the next AA or UA flight. It's the middle of the summer and flights are often overbooked. If nothing else, the decent seats will likely be gone. Thus, the service recovery is not likely to be particularly pleasant.
This, to me, is the key point - even if you find availability, the chances of it being available in F is pretty remote, including on the next day's flight given most upgrades will already have been processed.
There was a very grave danger of me missing a red-eye connection at LAX a couple of weeks ago on the A321T service to JFK, and it would have been many, many days before a space became available in J - all recovery options involved sitting in Y.
Unfortunately, this is one of the risks we take with ex-EU bookings - many of the flight times reduce the connection options considerably because of the later arrival, and full recovery becomes very difficult.