Yes, you can upgrade your seat on American Airlines through several methods. You can use AAdvantage miles to request an upgrade, or bid for an upgrade via the “Bid for Upgrades” program. Additionally, you can purchase an upgrade at booking or during check-in, if available. Elite status members may receive complimentary upgrades, particularly for domestic flights, depending on seat availability. Upgrades are subject to availability and fare class, so it's best to check early and often.