Quotes of the Day

One of the most common pieces of advice for air travelers is, hydrate. But, of course, carrying bottles or cups of liquid through security is verboten, and paying four or five bucks for a bottle of water inside security is just another indignity that flyers would prefer to avoid. The solution? Buy a non-disposable water bottle and fill it courtesy of a friendly server at an airport restaurant, or at a water fountain or bathroom faucet. (Local, state and federal regulators monitor water quality and safety at U.S. airports; however, do not drink the tap water aboard the plane.) Toting your own water bottle also cuts down on waste — according to California's Department of Conservation, a billion plastic bottles end up in landfills each year in that state alone. Below, five reliable, durable and green alternatives to the plastic water bottle.

Nalgene Tritan Wide-Mouth Everyday Bottle
The reasonably priced U.S.-made Nalgene brand bottles have long been popular with sportsmen and women, office workers and soccer moms. But in 2008, the company found itself, along with other bottle makers, in the eye of a storm over BPA, shorthand for Bisphenol A, a commonly used plasticizer that some researchers suggest poses a health risk to humans. The debate goes on; meanwhile Nalgene is promoting a new line of BPA-free bottles. I tried the 32-ounce Tritan Wide-Mouth Everyday bottle, which holds enough water to hydrate you on a coast-to-coast flight or for a full day at the office. The mouth of the bottle is large enough to accommodate ice cubes, but that also means sipping can be dodgy on bumpy flights. Nalgene sells a variety of accessories to solve that problem, including a pop-up sports cap. Price: $11.50

Camelbak Better Bottle
This sports bottle won't spill thanks to its "flip, bite-n-sip" design, even when the flip lock is left open. That makes it ideal for driving, or drinking in a middle seat on a full flight. Made with BPA-free plastic, Camelbak's Better Bottle has a sporty design, complete with a bottle-top loop that can be clipped with a carabiner to a backpack; optional sports caps also are available. I opted for a conservative blue-gray bottle, but it comes in lots of colors and patterns, including argyle and houndstooth for more urbane sippers. The internal straw and bite mouthpiece made cleaning the bottle a little more tedious, especially after filling the bottle with iced tea, but it can be washed in the top rack of the dishwasher. Price: $11 (0.5 liter); $13 (0.75 liter); $15 (1 liter)

Sigg Traveler
The sales clerk at Whole Earth, an Austin, Tex., based outdoors store, told me Sigg is considered the "hippest" of all water bottles, favored by such celebrities and eco-stars as the Dave Matthews Band. The Swiss company Sigg has been making lightweight, recycled-aluminum bottles for a hundred years; inside, they're lined with a secret coating to prevent the aluminum from flavoring the contents. The Sigg Traveler certainly is light and trendy-looking, and comes in two sizes and a variety colors, including classic, simple steel. One problem for those of us living in hotter climes: The bottle's mouth is too narrow for ice cubes. Also, metal water bottles can be used for warm beverages, but not boiling hot, and they sweat when filled with cold liquids — but Sigg, ever the savvy marketer, offers solutions: a hip Sigg carrying pouch and even a new hot-beverage Sigg. For cleaning, the company sells a specially designed brush and cleaning tablets. Price: $21.99 (0.6 liter); $24.99 (1 liter)

Klean Kanteen
This was my favorite. Sturdy — actually, dings and dents are marks of a seasoned traveler, the clerk assured me — with a mouth wide enough to allow ice cubes, but narrow enough to sip without spillage (sports caps are available too), the Klean Kanteen 27-ounce stainless steel bottle kept ice water cold for a two-hour-plus flight. The Kanteen comes in four other sizes, including a 12-ounce "Sippy" for babies, and seven hues — in plain gray steel for us minimalists, and enameled exteriors in vivid, solid colors like Ocean Blue and Orange Sunset. Like the Sigg and the Camelbak, the Kanteen fits easily into a car's beverage holder (the 32-ounce Nalgene Tritan was too wide, but Nalgene does make narrower bottles). Klean Kanteens are made in China by an American company, are easy to clean and because they're stainless steel inside and out, flavors do not linger after washing. Like the Sigg, the Kanteen can accommodate warm liquids but heat will transfer to the outside. If you are lost in the wild (and know how to start a fire) you can even boil water in the Kanteen. Price: $17.95 (27 ounce, steel); $19.95 (27 ounce, colored)

Platypus Platy Bottle
For barebones price and packability, the Platypus is a winner. Made with BPA-free plastic that is strong enough to withstand freezing and boiled liquids, the little 0.5-liter bottle rolls up into a small package that weighs less than an ounce. Filled, it measures 5 inches by 7.5 inches and has a gusseted bottom so it stands up. The sides are curved to facilitate easy gripping. Larger sizes are available, but this little gem is a great solution for travelers concerned with packing light. The only downside is the narrow pop-up mouthpiece with a loop-less, removable cap that, much like the ubiquitous commercial water bottle, requires you to use two hands — one for the cap, the other for the bottle — to drink. Price: $6.95 (0.5 liter); $7.95 (1 liter); $9.95 (2-plus liters)

• Hilary Hylton
• The most reliable, durable and environmentally friendly water bottles you can't travel without