AA went with the 111 (series 400) because in principle it was available
a year or so before the DC-9. They were supposed to arrive in early 1965 but
as others have pointed out it wasn't until early '66 that they went into service.
The 111 was an interesting aircraft to fly in -- very exciting -- and didn't have leading edge devices so landing speed was high, a real thrill, but it tended to scare passengers. Folks at AA tell me the cockpit crews referred to the 400 as
the 'kamikaze' for just this reason.
As TAD pointed out, they left AA's fleet in1972. None ever made it into the red white and blue scheme. When the oil crisis hit in 1973 AA commented that they wished they hadn't retired the 400 because some economical two-engine equipment would have been useful when fuel prices skyrocketed.
CV990, the Maserati of the skies!