BEND, Ore. (CNN/Money) - If negotiation is an art, negotiating for travel discounts and freebies is nearly a lost art. Many leisure travelers are reluctant to ask for a second pack of peanuts on the plane, let alone upgrades, meal vouchers, or hotel discounts.

"A lot of people are too timid to ask for things when they're traveling, but they shouldn't be," said Don George, global travel editor for Lonely Planet Publications. "The system is far more flexible than they think."

True, the rules for negotiating travel deals aren't as clear as, say, haggling over the price of a car or a house. Still, you'd be surprised by how easy it is to get what you want just by being friendly but firm, talking to the right person, knowing what to ask for and, in some cases, letting other people do the negotiating for you.

Perhaps you dumped your travel agent and started researching and booking your trips online years ago. But while the Web gives you access to a lot of the same information available to travel agents, these professionals still have a leg up when it comes to negotiating big-ticket discounts.

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"I often find that calling a travel agent is the best way to get a deal," said George. This is because agents typically belong to large travel networks they can negotiate deals that individuals could never find on their own. In some cases, they are privy to air, car rental, and hotel packages that cost less than what you'd pay just in airfare alone.

Thanks to multimillion-dollar travel budgets, large companies are also able to negotiate incredible discounts with airlines, hotels and car rental companies. As long as your company doesn't frown upon you using the corporate agency for pleasure trips, (many don't, since it only adds to their buying clout) you can save bundles by booking through the corporate travel department.

Just be sure to research rates before you go through a middleman. Sometimes it's still cheaper to book on your own.

There may be a dozen money-saving opportunities tucked in your wallet and forgotten, whether it's your American Automobile Association membership or your American Express card.

Many such organizations and frequent flier or guest programs negotiate travel discounts for their members. The trick is remembering what affiliation gets you what discounts and where. Although some reservations agents will ask if you belong to any such group, make it your job to keep track of these perks, and always ask if your membership warrants any special treatment. In fact, it's a good idea to write the names of all of your affiliations and their major partners on one piece of paper and keep it with your travel itinerary.

Airlines have gotten stingy when it comes to waiving flight-change fees or upgrading honeymooners to first class. But they haven't completely closed the gate on negotiation.

Your best opportunity to ask for freebies is when the plane is overbooked and the airline is looking for volunteers to take another flight. According to Tom Parsons, CEO of Bestfares.com, the percentage of people being bumped this year is (and will continue to be) particularly high. "This is because airlines cut their capacity and are getting fewer cancellations than they had expected," he said. Airlines typically overbook flights anticipating that a certain percentage of passengers will not show up.

While airlines can "bump" passengers involuntarily, they will try to avoid that by first soliciting volunteers with the promise of travel vouchers. The vouchers can be used to help pay for a future airline flight.

Typically, an airline will start with a smaller dollar amount and steadily up the ante until it has gotten enough volunteers. You can wait until the airline makes a generous offer, or do as Parsons recommends. That is, sign up to be bumped before the airline makes a general announcement (this puts you in front of everyone else jumping up to be bumped) and then ask for the highest voucher available when it's time to hand over your boarding pass.

"I tell them that I don't mind volunteering but I would appreciate getting the best deal of the day," said Parsons.

When you're haggling for the best deal, you can use the price of your ticket as a negotiating point -- assuming that your ticket is worth more than their best offer. If you paid $500 for the flight, you should by all means try to get a $500 voucher for delaying your trip. Also, ask for the airline for things like vouchers for meals, phone calls or admissions to the executive club to help pass the time while you're waiting for the next flight.

Seat upgrades are extremely hard to come by now that so many frequent fliers use their miles to fly first class and business class, but there's no harm in asking. "Be real nice and remember that appearance is important," said Parsons. "If you're in a T-shirt and haven't shaved for a week, they're probably not going to put you up with the first class passengers."

It is also perfectly appropriate to ask about vouchers when your flight is severely delayed or canceled. If the airline is responsible for your delay, whether because of a mechanical problem or a scheduling glitch, you should ask the airline to accommodate you. They often won't offer you anything unless you ask for it.

Be nice, though. You're more apt to get what you want if refrain from taking your frustration out on the agent. Still, you should point out that your inconvenience was caused by the airline and that you expect them to make good on their error. You might first ask them to exchange your ticket for a similar flight with another carrier. If you'll be held up overnight, you might ask for meal and hotel vouchers, as well as transportation and phone vouchers.

If the airline is not at fault for the delay, such as when there is bad weather, you shouldn't expect any favors, but don't let that stop you from asking. "My strategy is to show that person that I'm reasonable," said George. "I might start by saying, 'I know this is a little out of the ordinary but would it be possible to...'"

There are plenty of opportunities to barter car rental companies, especially when their lots are full. First, shop around and reserve the best deal, keeping in mind any discounts you get through your company, membership organizations or airline. Rental car cancellation policies are generally fairly lenient, so feel free to keep shopping after you've made the reservation.

"Always book a compact car," said Martha Gaughen, a certified travel agent with Sterling Travel in Atlanta. "The likelihood of being upgraded when you pick up your car is pretty high because rental companies typically run out of compact cars." Even if the car rental hasn't run out of cars, you may be offered to upgrade for less money than you would have paid to book the larger car in the first place.

If you're picking up your car at an airport, where there are dozens of rental companies right next to one another, you can try to play one car rental company off of the other. "I ask other car renters at the airport if they can beat that rate. Even if it's the same rate I ask them if they'll give me a free upgrade," said Parsons.

Even then, the negotiations don't stop until you reach the lot. "If you notice that the lot is filled with luxury cars you might just ask if you can have one at no extra cost," said George.

The price of a hotel room is far more flexible than many travelers assume. Although you may not have much luck haggling over the price with the reservations agent, you should always ask if you're getting the best rate when you check in. Sometimes hotels are willing to extend corporate rates or AAA discount to anyone who asks for them.

Tom Parsons says that you don't have to limit yourself to the hotel's best rate. You can even try asking for its competitor's best rate. "You can also ask about room upgrades or a bed and breakfast package for the same price as the room only," he said.

Keep in mind that your chance for success has a lot to do with demand. Prices won't be very negotiable during the peak of the travel season, says Jani Miller, a certified travel agent with Central Travel in Toledo, Ohio. But during low season or remodeling, or at a new hotel or business hotel on weekends, there is often some leeway. This is particularly true if there are several people in your group. "Usually 20 room/nights is cause for negotiation," she said.

You can also question the price of your room if the experience is not up to par. Maybe your room was next to a loud elevator or reception hall, the television didn't work, or a tournament kept you off the tennis courts or golf course.

"Even if your hotel doesn't provide a requested wake-up call or there is construction at 7 a.m. on a Saturday morning, complain and ask for consideration on your hotel bill," said Kathy Sudeikis, a certified travel agent at All About Travel in Mission, Kan.

When making a complaint, be sure to speak with someone who has the authority to reduce your room rate or issue a gift certificate, and keep your expectations in line with the hotel. "The staff at hotels that put a strong emphasis on service are trained to do whatever they can to make you happy," said Martha Gaughen, a certified travel agent with Sterling Travel in Atlanta. Don't expect big make-good discounts at a bargain-rate hotel chain.