Many airlines, including American Airlines, offer a window of time during which you can cancel or change your flight without incurring a penalty fee. Here are some tips on how to cancel your flight without penalty:

1. Check the airline's cancellation policy: Before booking your flight, make sure to read the airline's cancellation policy to understand the window of time during which you can cancel without penalty. This information should be available on the airline's website.
2. Cancel within 24 hours of booking: If you need to cancel your flight, do so within 24 hours of booking to avoid any cancellation fees. This applies to all fare types, including non-refundable tickets.
3. Cancel or change your flight at least 24 hours before departure: If you need to cancel or change your flight, make sure to do so at least 24 hours before departure to avoid any penalty fees. You can usually do this easily through the airline's website or mobile app.
4. Consider travel insurance: If you're concerned about the possibility of needing to cancel your flight, consider purchasing travel insurance. This can help protect you in case of unexpected events, such as illness or a family emergency.

Remember, each American Airlines Cancellation Policy may differ, so it's important to check with the airline directly for their specific guidelines and fees. By following these tips and understanding the airline's policies, you can cancel your flight without penalty and minimize any potential fees or complications.