Jet lag can occur when you travel across time zones and your body has a hard time adjusting to the timedifference. The maximal time difference you can have is 16 hours which is if you travel from Los Angeles to Hong Kong.
I travel a lot between New York and Europe. Almost every month I have a round trip crossing the Atlantic Ocean. Traveling in Europe or to Tel Aviv is just 2 hours time difference (in example from London to Tel Aviv) so that is not so hard for the body to adjust to.