Traveling to far off places has become common as our world shrinks. Whether for business or pleasure, far more people are seeing the world. One fairly common complaint is jet lag. Jet lag or desynchronosis, "is a physiological condition which results from alterations to the body's circadian rhythms".
BEFORE YOU GO: For me, the most effective thing I do is done the day before I go. I set my watch to the new time zone and I set my intention to be there, in that time zone. I agree with Sensei Sasanuma, to keep yourself in the moment. While you are on the plane or at your new destination, don't keep looking at your watch saying "gee, back home it is...".
ON THE PLANE: EFT works well. Every couple of hours on the plane you can tap on the energy points with the statement “it's 2 am (or whatever the new time zone time is), and my body is adjusting well. Check with an EFT practitioner to learn how.
Of course all of the other advice out there pertaining to drinking lots of water, avoiding caffeine and alcohol, walking around the plane etc. are all valid as dehydration can contribute to general symptoms, but what we are interested in is your circadian rhythms.
WHEN YOU ARRIVE: If possible, being mindful of safety issues, go out to a park or somewhere where you can connect with the earth (even a tree outside your hotel will do). Deep breathing while connecting to the earth reconnects your energy system to the frequencies of where you are. Being out in the fresh air helps to rejuvenate the body and sunlight will signal your hypothalamus to reduce the production of (sleep-inducing) melatonin during the day, helping to reset your internal clock.
Lemon grass has a stimulating effect and is a powerful antiseptic. It has a sedative effect on the central nervous system and is useful for headaches. You can put a small amount on a cotton ball and put it in the heating vent to improve the air quality.
If you arrive in the evening apply a few drops of Lavender on your wrists and the bottom of your feet to help you sleep. You can take a warm bath with a few drops of Lavender as well. Lavender has anti-inflammatory properties which may help with swelling.
If you arrive during the day use Peppermint to revive. It has uplifting, stimulating, and immune-boosting properties. Inhale or put on a compress, being careful not to get in your eyes.
Bon Voyage!