The price of a first-class plane ticket is over budget for the average person. Everyone would like an upgrade when flying, but it's difficult to get one without paying for it. There are obvious tactics, such as simply asking for an upgrade at the check-in counter or traveling alone to increase your chances, but other methods may also help you snag that free upgrade.

United's Mileage Plus Program

Sign up for Mileage Plus through the United Airlines website. Be sure that your name and other identifying information matches your government-issued ID, such as your driver’s license.

Earn miles by using your Mileage Plus account when you book flights. The ratio for miles earned varies depending on the type of flight you book. First-class tickets earn you 150 percent of the miles you travel as redeemable mile credits, business class is 125 percent and discount business class, economy and discount economy earn you 100 percent mile credits.

Redeem mileage credits with United Mileage Upgrade Rewards for free one-way, one-cabin upgrades for flights you purchase on United or United Express flights. Upgrades depend upon seat availability, and you may not be able to request the upgrade until the date of your flight. If no seats are available before the day of your flight, you will be put on a waiting list.

Other Tactics

Wear your military uniform for your flight or check in using your military identification. If upgrade seats are available, United attempts to provide servicemen and women with this free option as a sign of appreciation.

Book airline flights that are likely to fill up by the departure date and be flexible with your destination plans. Prime examples are weekend flights, flights on peak holidays (spring break or Christmas) and flights to popular holiday destinations (such as Orlando or Cancun). There is more chance that United will overbook these flights and, if so, offer willing participants an opportunity to take a later flight in first-class seats.

Obtain credit cards that offer a travel rewards program connected to United Airlines. These cards charge an annual fee, but if you travel frequently, the upgrade savings typically make the fee worthwhile. You can check the latest offers on United's Mileage Plus partner guide (see Resources).