Am I allowed to fly from Australia on Motzei Shabbos?

Question

If I take off from Melbourne on Motzei Shabbos, I will hit the Date-Line, loose a day, and end up flying on Shabbos for a short period of time until the sun catches up again. Am I allowed to do this?

1. Do I have to keep Shabbos for that time?
2. Is this forbidden the same way embarking on a ship less than 3 days before Shabbos is forbidden?
3. If I daven, do I have to Daven Shabbos davening or Weekday?
4. Do I have to do Havdala after that small period of "Shabbos"?

Answer 1

R. Michael Broyde responded to a similar question about flying to Australia erev Shabbos, in which case one would start before Shabbos and then all of the sudden be at the end of Shabbos. R. Broyde distinguished between two cases: when it becomes Shabbos on the plane and then skips ahead to the end of Shabbos (in which case, this should not be done lechatchila, unless one's livelihood is at risk), and a case where it goes from pre-Shabbos to the middle of Shabbos (which one should not do under any circumstance). In the former case, one would simply observe Shabbos for the hour or two on the plane. In the latter case, one would not observe Shabbos at all, since "one cannot 'poof' appear into Shabbos," and thereby nullify a positive mitzvah.

Answer 2

Flying on a plane before shabbos is not like embarking on a boat regardless of the reasoning (I remember 4 offhand):

1. The sea-sickness will breach your kavod shabbos: Anyone who has been on a medium size boat in the ocean without dramamine knows that this is no comparison to flying on a plane which is pretty smooth.
2. The crew is doing melacha for you: Does not apply if most of the passengers are not Jewish.
3. You will be forced to do melacha in a dangerous situation: No weather satellites back then, so it was common to run into a storm and have to violate shabbos. Not true with a plane ride. Besides, what are you going to do?
4. You may not travel beyond the techum on shabbos: If you are above 10 tefachim before shabbos, you are not subject to techum.

(At some point I'll bring sources and other possible issues that don't apply.)

I asked my Rav regarding my neighbor who travels to Asia and Australia. He said that although the Chazon Ish could do it, we would have a problem. The Chazon Ish would keep Friday and Friday night until he got to the Asian coast, then it would be Saturday night. But since there was never a clear ruling on the dateline, once we cross the international dateline (but before the Chazon Ish's dateline) we would be in doubt about our obligations. That night, are we obligated in kiddush or havdala? It might be possible to work it out a situation where there are no doubts, but I haven't tried.

I hope it is clear that you must keep the "little" shabbos and make havdala. Of course you'll have to ask someone to stand in front of the lavatory for you since the light will go on if you slide the lock!

Answer 3

R. Nachum Rabinovitch holds that when a person flies on a fast day, one is still considered in the place of departure until he reaches his destination. I don't know if the same would apply l'kula to shabbos, which is more chamur.