American Airlines never operated the 880. The aircraft is a Convair 990 Astrojet. The clear difference is the size of the engine intake diameter, given that the 880 was powered by GE CJ805-3 turbojets which produced 11,650 lbs st., versus the 990's CJ-805-23B turbofans, producing 16,050 lbs. st. each. Unique to the CJ805-23Bs was the aft located bypass fan stage.