http://www.star-k.org/kashrus/kk-trav-dateline.htm
"Similarly, it is preferable that one should not depart from these locations (to fly east toward America) on Friday."
What do the Halachic Authorities say about taking a flight Friday AM in the winter back from say Tokyo or Seoul where it gets dark for a short while during the flight?
Example A:
27 Dec 2012 American Airlines 134 HND 06:50 JFK 05:35 777 0 1234567 12:45
Example B:
27 Dec 2012 Korean Air 81 ICN 10:20 JFK 10:00 388 0 1234567 13:40
According to GCM, both flights take a similar route back over Siberia and the rest of Europe
Then it would be flying
West, and would probably be over China/Russia land before it becomes dark.
Also, as far I know, there is no issur being onboard an aircraft during shabbos, provided one makes kiddush and havdala onboard.
Is there some kind of issue with having two shabbosim in one week?
An interesting fact is that SQ21 can travel either way across the globe, depending on winds. Also, IATA has trouble defining SQ26 as TPAC or TATL, as it is both.