PLEASE HELP ME WITH SOME DOMESTIC FLIGHTS THAT HAVE A QR CODE
And would that mean that they are 'operated by AA,' and 'marketed by QR?'

From: 19 May 2020
Qatar Airways and American Airlines have formally started their partnership with the Doha-based carrier placing its QR code on American domestic flights.

“The codeshare will be rolled out in phases over the next few weeks and, once completed, will see Qatar Airways’ code placed on over 1,000 of American Airlines’ domestic flights connecting with Qatar Airway’s 10 US gateways,” Qatar Airways said in a statement.

The first phase of the codeshare partnership will enable Qatar Airways’ passengers to book travel on American domestic connections via Chicago O’Hare (ORD) and Dallas-Fort Worth (DFW) airports to 200 American destinations, including Atlanta (ATL), Detroit (DTW), Houston Intercontinental (IAH), Miami (MIA), Minneapolis/St. Paul (MSP), San Francisco (SFO) and Seattle (SEA).