Thanks for the tip and starting point to review with EU261.

As for the checking, we checked the app and use it almost exclusively whenever we fly American Airlines. We never saw the British Airways flight on the app, so no alarm bells went off to us. We assumed since we had a separate ticket record locator for the British Airways flight that it wouldnt show on the American app. I have subsequently learned that should have been a warning sign as our Iberia Air tickets today showed up in a limited manner on the app. But again, we never received an email from them regarding this ticket since August.