The information has been updated.

First- and business-class seats are highly coveted by both elite flyers and award travelers who want to upgrade. Bidding for unsold premium cabin space is one way airlines are competing for it.

The bidding process and which airlines offer the service are covered here. We offer tips to help you find better prices on some of the most popular airlines.

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The bidding process

The upgrade bidding process is the same for different airlines. After you have completed your booking and received your e- ticket, you can initiate your bid.

1. An email will arrive offering you the chance to bid on an upgrade.

2. You can go to the airline’s website and see if your booking is eligible to bid on an upgrade (you'll often see a pop-up offer or a tab to click on to begin a bidding process).

Standard rules seem to apply when it comes to terms and conditions for bidding on upgrades.

1. You may only place a bid after you have a ticketed reservation.2. There is a minimum and maximum allowed bid per flight segment. You can’t just bid $1 in the hope no one else bids.3. Not all routes are eligible. Some airlines specifically state which routes qualify, while others make you enter your booking confirmation code to see if your flight is eligible.4. Upgrade bids are per segment and per passenger on your itinerary. For example, if you’re flying from Los Angeles to Paris to London, you must make a bid for your Los Angeles to Paris flight and then your Paris to London flight. Your bid will be understood as per person if multiple people are on your ticket. If there are two people on your itinerary and you bid $200 for the segment upgrade, your bid is understood as $400.5. Depending on the airline, there are certain time windows in which you can place your bid. Most require all online bids to be placed at least 72 hours prior to departure.6. You must enter payment information at the time of booking, but you will not be charged unless your bid is accepted. All accepted bids are nonrefundable unless your flight is canceled.

7. If successfully upgraded, most programs give you all the perks and benefits of your new travel class, including lounge access and extra baggage allowance. We listed exceptions below.

Aer Lingus business class aboard the airline's Boeing 757 (Image via Aer Lingus)

Aer Lingus business class aboard the airline’s Boeing 757. AER LINGUS

Airlines that offer bidding for upgrades

The company that runs most airline bidding programs seems to be Plusgrade. Each airline has a limit on the program. There is a list of the bidding processes for each.

Some flights between Ireland and North America or Canada are eligible for upgrade. On flights booked directly with Aer Lingus, you can only bid for upgraded flights. The email will be sent to customers who are eligible.

Passengers on international flights can upgrade to one class with the OneUp program. It's possible to move from economy to premium economy or from economy to business premier. You can upgrade from economy to business if there are only two classes on the plane. You can submit a bid by email up to three days before departure, or through the airline's call center. Seven days before departure, successful bidder are notified. Cash or Airpoints Dollars can be used for payment.

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The upgrade is not restricted by location. Those who use promotional fares, guest seat rewards, redemption tickets, free tickets, those upgraded using miles, multi-flyer tickets and bookings with infants are not eligible to bid for an upgrade. One class can be upgraded from economy to business or business to first. If your bid is successful, you will receive a 10% class of service bonus.

Premium economy can be upgraded from economy on long-haul flights. Premium economy passengers can bid for business class and first class travelers can bid for first class. Business class upgrades can be bid for by economy passengers. To submit your bid, you need to log in to the website. If your bid was accepted, you will get a notification before you leave.

ETIHAD

How to make sure you get an upgrade on your flight.

For flights booked through and operated by Singapore Airlines, you can upgrade in cash or KrisFlyer miles. You can change your mind up to 72 hours before your flight. If you pay with KrisFlyer miles, you can upgrade one class. If you pay with cash, you can upgrade to first class if you choose.

If you want to upgrade to the next higher class of service from the ticket you booked, Virgin Atlantic will allow you to. If your flight is eligible, you will get an email invitation to make a bid. You can make a bid up to two days before you leave.

Airlines that don’t offer bidding for upgrades

The airlines don't allow you to set your own amount to bid for a chance at an upgrade, and they may allow fixed-price upgrades using cash and/or miles.

  • Air France/KLM.
  • American Airlines.
  • British Airways.
  • Delta Air Lines.
  • Emirates.
  • Qatar Airways.
  • United Airlines.

airplane seat

DANIEL ROSS/THE POINTS GUY

Tips

There is no plan to make sure you are the winning bidder. These tips should make a difference.

  • Use ExpertFlyer or a similar tool to see how many premium class seats are still available on your flight.
  • Follow this equation for a bid price: Calculate the regular cost of a business class seat. Subtract what you paid for the economy fare, and aim for around 20% to 40% of the remaining price.
  • Bid slightly above the minimum to beat the crowd, since most people will choose the minimum.

Many elite-status members feel that their hard-earned operational upgrade chances are being auctioned off because their preferred airline is offering bidding. Flat-fee upgrades at the check-in counter and boarding gate make it more difficult for top-tier elites who are high on the upgrade list to get there. It is difficult for airlines to keep their most loyal flyers happy while maximizing revenue.

Melanie Lieberman won a flight upgrade for a SAS flight from the New York City area to Norway. Passengers can bid on upgrades until 25 hours before their flight. Melanie moved from the economy class to the business class. She discovered that travelers can win upgrades by bidding the minimum price. She was told that business class on her flight was open.

SAS

One reader told us that they were able to get flight upgrades with PlusGrade quite frequently. Travelers can check for bidding opportunities if they use PlusGrade. A reader successfully bid for an upgrade on a flight from the east coast to Africa.

Bottom line

Bidding for upgrades has the potential to be very good. If you offer up a couple of hundred dollars or pounds, you can find yourself in premium economy or business for less than the amount paid by your new neighbors.

If you ever get the chance to bid on one of these airlines, make sure your offer is worth something. The strategies above can help you fly in premium classes at a lower price.

RedVentures is the parent company of Expert Flyer.

Ben Smithson reported additional information.