Thanks all, and apologies I wasn’t clear. I meant XXX to be any USA destination. So this is USA to USA with layover in MEX.

AM or Aerolitoral/AMConnct fly to a handful of places depending on time of year.

LAX/SFO/IAH — MEX (AM ticket, AM code, Aerolitoral metal)
MEX — JFK (AM ticket, AM code, DL metal)

MEX — JFK is marketed by both and operated by DL, but ticket would be AM ticket/code