“New Small Narrowbody Aircraft” means a CS100, E190 or E195 aircraft, provided that such aircraft is neither in the Company Fleet as of the date of signing of this Agreement nor acquired through merger or acquisition of another air carrier.

The emphasis is on "small" meaning a plane with approximately 100 seats. The idea being to continue enabling flying being done by express carriers into smaller airports using 76 seat airplanes to migrate back to mainline on a 100 seat plane.

An A321 seats 180 pax. It is a Narrow Body, but it is anything but "Small".