AA BE fare cancellation fees are listed on this page -- https://www.aa.com/i18n/customer-ser....jsp#ticketing
They range from $99 to $199 which is similar to what DL charges. Although DL's fees are either $99 for domestic/Canada or $199 for international (they don't have a $129 fee level). Note that you are required to be an AAdvantage member to qualify (although you don't need any form of status). UA is even worse about BE cancel fee disclosure and fees and they range from $149 for domestic to $249 for international. As far as I'm aware, the only place UA discloses these are in the fare rules (in Penalties section) after you have selected flights.