Since flight rules dictate what foods and drinks you can carry onto a plane, you often have to plan ahead. Sometimes that means you spend money you don’t want to on expensive airport food, pack light snacks that will pass TSA, or opt for plane food.

And plane food is typically plain food. What if you forget to plan ahead? Should you go with what the flight attendants hand out? Tasty peanuts, pretzels, or cookies await you, as do sodas, water, and suspect airplane coffee. Maybe you think about roughing it and fasting during your flight. Don’t!

We’ve already warned you about what not to drink. Stay away from tea, coffee, or airplane tap because the potable water is not the cleanest. But when that drink cart comes your way, there’s one thing you should definitely ask for: bottled water. Not soda, not juice, and not alcohol.

Southern Living’s video explains how crucial it is for your body to stay hydrated during a flight and why water is your lifeline. Flying dehydrated can contribute to air sickness, leaving you prone to nausea, dizziness, and vomiting. Drinking water before and during your flight can help prevent you from becoming ill. You want to do so regardless of how long your flight lasts.

Poor hydration can also cause or worsen jet lag. Who wants to spend their trip too worn out to enjoy it? While many people like to request tomato juice or alcohol when flying, both types of beverages will could potentially put you on the dehydration highway with a destination of fatigue.

Bloody Marys and tomato juice are popular choices on planes because taste buds love the umami flavors. At high altitudes, they soar. Tomato juice is typically high in vitamin C, but guess what? It’s usually high in sodium too, which can contribute to water retention in the body and dehydration.

Having an alcoholic beverage can also throw off your electrolyte balance. That spells bad news if you’re trying to avoid jet lag or a potential headache. You will run to the bathroom and be thirsty all over again because your throat is parched, and your system is running on empty.

Cabin pressure and humidity are other factors that create conditions for dehydration, and there’s not much you can do about that other than prepare or prevent the worse case scenarios. Choosing soda, booze, or something salty should be avoided if you want to stay properly hydrated.

If regular water doesn’t float your boat, ask the flight attendant to pour you some bubbly seltzer water with a splash of cranberry. This fizzy mocktail is good for settling upset tummies, has a splash of germ-fighting vitamin C, and can meet your needs for water intake.

In this case, you don’t want to stay thirsty, my friends. Click on the video below to hear more about how what you drink on a plane can affect your trip.

What’s your usual drink order on a long flight? What do you think about this advice? Are you prone to airplane sickness, dehydration, or headaches when flying?