Now that nearly every airline is charging baggage fees, travelers are motivated to pack as efficiently as possible. And who knows more about packing than professional flight crews? In interviews with a dozen flight attendants and pilots, one theme emerged: To pare down and still have everything needed at the destination, think strategically. Where you're going and what you'll do there should guide packing, but it is most important to know your absolute essentials. 'I try to pack everything I'll need to survive,' said Leigh Johnson, a retired American Airlines captain. The ability to wash shirts and underwear is important to him, so Johnson brings laundry soap. And because he often arrives at the airport for a flight before the restaurants open, he packs food. Professional travelers also pack personal electronics like e-book readers and laptops. Patrick Smith, an airline pilot who writes the Salon column Ask the Pilot, often brings a camera so he can post his travel videos online. To make room for these new travel necessities, many flight attendants roll their clothes rather than fold them to save space. Nerea Gomez-Cambronero, an attendant with Air Europa L?neas A?reas in Majorca, Spain, has taught friends and relatives to roll-pack clothes. 'The rolling-your-clothes tip is the basis of my entire company,' said Don Chernoff, an engineer and frequent traveler, whose www.skyroll.com offers a line of luggage that encourages rolling rather than folding. Weather and terrain create the biggest packing challenges. Coats, hats and umbrellas are cumbersome. Jay Abramson, a captain with Continental Airlines, avoids bringing heavy garments even in winter. 'A thermal T-shirt and long underwear will allow you to wear a sweater and a fleece or lined windbreaker down to the mid-20 degrees,' he said. Fred Arenas, a corporate pilot, travels with just one pair of shoes, the ones on his feet in the cockpit. Johnson, an avid outdoorsman, wears his hiking boots onto the plane rather than pack them. While deciding between what's essential and what's extra is highly personal, Chernoff, the luggage designer, has advice that's universal. 'Think hard about what you are doing,' he said. 'Pare down what you are going to bring. Then, when you're done, pare it down again.' 