Yes, pilots who hold a Type Rating for the Airbus A320 are automatically qualified to fly the entire A320 Family, which includes the A318, A319, A320, and A321. This is possible because Airbus designed these aircraft with "Flight Crew Commonality" in mind. The cockpits, systems, and handling characteristics are virtually identical across the fleet. While the A321 is significantly longer and heavier than the A320, the fly-by-wire system "normalizes" the feel of the aircraft, so it handles very similarly to its smaller siblings. Pilots only need to undergo a short "differences training" course to understand the specific performance nuances of the A321—such as its different tail-strike margins and take-off speeds—but they do not need a separate license. This commonality is a massive financial advantage for airlines like Delta or JetBlue, as it allows them to schedule a single pool of pilots to fly any aircraft in the A320 family based on daily demand, significantly increasing their operational flexibility and reducing training costs.