You can boost your odds of receiving your preferred seat, extra legroom and a flight that leaves on time. By Sean O'Neill May 31, 2006 1. The aisle seat you thought you had? Gone. Your seat assignment isn't a done deal until you're holding a boarding pass, even if you selected a seat when you bought your ticket. (One exception: Northwest Airlines is testing guaranteed reservations for aisle and exit-row seats for a fee of $15 for each leg of the flight.) Boost your odds of receiving your preferred seat by checking in online. Most airline Web sites allow you to check in within 24 hours of your flight's departure. RELATED STORIES Fly Through Security Summer Travel Planning Guide 25 Best Value Travel Sites 2. Try saying "pretty please." Airlines give their airport agents discretion to assign seats and make other decisions. Use them. Last year, five months before Ken and Kari Dilloo were set to take an Alaska Airlines flight to Zihuatanejo, Mexico, they visited the Seattle airport counter of Alaska Airlines and asked for seats with extra legroom. Says Kari: "It was completely worth it for the more-than-six-hour flight on our honeymoon." 3. If they bump you, make them pay. Hold out for the best deal. Last year, 47,774 confirmed passengers were bumped from their flights against their will. Every major airline with large aircraft, except for JetBlue, denied boarding to some passengers. If your airline bumps you, it must rebook you on a later flight and compensate you with up to $400 in cash or its equivalent, according to federal rules. The gate agent may offer you a voucher for a free or discounted future flight instead of cash. But many vouchers come with restrictions, such as a one-year expiration, so cash is usually the better deal. If, however, a gate agent asks for passengers to give up their seats voluntarily, note that the agent could up the voucher ante to as much as $1,000. 4. Stretching your legs is a luxury. Most airlines offer seats in economy class with only 31 inches of legroom. An exception is JetBlue, whose seats often provide 34 inches of legroom. Barry Rogers of Evanston, Ill., a business traveler who is 6 feet 3 inches, offers this tip: Determine the legroom and quirks of a seat before you book by visiting SeatGuru.com, a site that details the seating on planes flown by 29 airlines. Advertisement 5. They could run out of peanuts while you're waiting to take off. On average, one out of five planes was delayed last year, and the percentage of delayed planes has increased over the past few years. To avoid sitting on the runway, book one of the first flights of the day. A flight that originates at the airport has a sporting chance of departing on time. 6. B.Y.O.B. -- blankie, that is. Today's Greyhounds of the skies are even skimping on blankets. In a recent test, American Eagle charged $5 for a pillow-and-blanket kit. So consider toting the following items to add to your comfort: The Cabin Cuddler blanket ($35; www.cabincuddler.com) boasts a unique shape that is easier to wrap around your body than an ordinary, rectangular blanket. (Says David Rowell, who writes the online newsletter The Travel Insider, "It's my favorite blanket.") The Hedbed inflatable travel pillow ($10 at Campmor.com) is comfy but small enough for easy packing. And Beyond BodiHeat's self-adhesive heating pads will soothe your muscles for hours (ten pads for $10 at Drugstore.com).