https://airlinespolicy.zohodesk.com/portal/en/kb/articles/24-hour-cancellation-what-is-delta-s-cancellation-policy https://riversideca.gov/sites/default/files/webform/musueum/covid/delta-airlines-24-hour-cancellation-policy.pdf https://riversideca.gov/sites/default/files/webform/musueum/covid/what-is%20american-airlines-cancellation-policy.pdf https://riversideca.gov/sites/default/files/webform/musueum/covid/what-is%20united-airlines-cancellation-policy.pdf