Purchase a Y-class airline ticket on an AirTran flight.
Check in for your flight either online, at a check-in kiosk or with a ticketing agent at the airport. If you check in online or at a kiosk, you will be presented with the option to upgrade your ticket to business class if there are seats available. The price for the upgrade will be displayed. If this is acceptable to you, select "Yes" and use your credit or debit card to pay the upgrade fees. To use your A+ Rewards credits, see a ticketing agent.
Inquire with the ticketing agent about available upgrades when you check in with her. If they are available, you can use your credit or debit card to pay the upgrade fee. You may also use your A+ Rewards credits to upgrade.
You may also choose to wait until you reach the gate to upgrade your ticket or check with an agent at the gate if upgrades were previously unavailable. The number of available upgrades can change due to passengers not checking in or being late for the flight. If there is an upgrade available, you may pay the gate agent your upgrade fee or use your A+ Rewards credits.