Originally Posted by
schmare
While you're rebooking the flights you should also check on the visa requirements for the double USA connection. Similar to a FRA-MXP connection, a double USA connection may require either a transit visa or a "real" visa.
better safe than sorry on this round of tickets!
Excellent advice.
I suggest using the following tool:
https://www.delta.com/planning_reser...tion/index.jsp
and checking what the rules are for transit and entry, country by country, based on the passenger's nationality/residency.
The US requires visas (including transit visas) for nationals from most non-OECD countries. The result of that is that transiting through two airports in the US is not a primary hurdle; the primary hurdle is getting the US visa in the first place.