Flight School.

Thanks to security regulations, packing has taken on a whole new meaning. Sarah Brown fits it all inside a Ziploc bag.

According to Transportation Security Administration (TSA) regulations, it is perfectly acceptable to tuck a wrench, screwdriver, cigar cutter, corkscrew, or scissors (with blunt ends) in with the magazines in your carry-on bag. But a free-floating lip gloss at the bottom of your purse--that offense will land you face-to-face with a frowning, plastic-gloved security screener.

Frequent and not-even-very-frequent fliers are painfully aware by now that all liquids, gels, and aerosols taken aboard a plane must be in three-ounce containers or smaller, and must all fit inside a single quart-size Ziploc bag. This means that packing, a once banal act, now requires cunning, strategic planning, and sometimes a little math. Ziploc, owned by the SC Johnson company, is the clear winner here, but the savviest travelers are rising to the challenge, too.

"Do you know how much I shoved into one Ziploc bag yesterday?" asks Marcia Kilgore, founder of Bliss spa and the new brand Soap & Glory, who has come to dinner straight from the airport and will be staying in New York for just 24 hours before flying back to London. "I actually pulled the floss out of the floss thing, so I didn't have to bring the whole package." Kilgore, who has made sure Soap & Glory staples like Flake Away body polish come in airplane-friendly sizes, too, has mastered the art of prioritizing: She left shampoo and conditioner at home ("It's usually in the hotel"), as well as her perfume ("I was sad about that"), in order to leave room for lip balm, cleanser, and her full-size bottle of Shiseido foundation. "That's worth carrying because it makes a difference--because, if you've been on a long flight, you don't look like hell," she says flatly (face glowing). "I'm a skin-care person. People look at my skin, not my hair." (I note she is wearing a hat.) "If I were Frederic Fekkai, I might be carrying some kind of gel ."

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