What to do:
Promote circulation. Wear loose-fitting, comfortable clothes to promote circulation (and sanity!). This is especially important, given that you're at a higher-risk for blood clots while flying and staying immobile for long periods of time.
Stretch & move. Keep your circulation optimal by performing simple stretches and practicing deep breathing. This is crucial for overall wellbeing, and also helps avoid aforementioned blood clots.
Eat right. Some say fasting is the antidote for jet lag. If that sounds a little extreme, try sticking to a light diet of fruit, smoothies, and salads the day of travel. Practice proper food combining to prevent bloating and aid in digestion (i.e. eat fruits on empty stomach, eat proteins last, etc.)
Stay hydrated (inside & out). Water is essential while flying. Drink 10 ounces of water for every hour in air. I buy the largest water bottle(s) possible once I'm through security. This keeps skin, hair, cuticles—everything!—hydrated.
Beat the bloat. A healthy way to do this is to consume natural diuretics, such as unsweetened cranberry juice, asparagus, watermelon, or cucumber.
Go easy on your digestion. Avoid sodium-laden and difficult-to-digest food, especially those with bloating affects, such as cruciferous vegetables, nuts, seeds, meat.
Limit alcohol. If partaking in booze, limit yourself to one drink and stick to something simple like organic red wine or a glass of bubbly.
Invert: Inversions reverse the flow of gravity, stimulate the lymphatic system, and aid in blood purification. Invert a few times the day of and after travel for 2 to 3 minutes. Typical inversions include: Legs propped against the wall, shoulder stand, headstand, or handstand.
Sweat: Working up a sweat helps combat water retention, jump-starts metabolism, stimulates the lymphatic system and gets blood circulating. Go for a quick job, practice yoga, or pop into a steam room.
Hydrotherapy: Take a hot bath with bath salts and a few drops of essential oil, or jump in the shower and alternate between hot/cold water in shower for 10 second intervals. This stimulates the lymphatic system, detoxes the body, and helps combat water retention that often occurs after travel.
Hopefully these tips make your next travel experience a bit more comfortable, beautiful and all-around enjoyable!