On January 1, 1980 Pan Am took over National Airlines. On the upside, for the first time Pan Am gained extensive domestic routes and restarted Paris flights.. On the down side, the merger marked a real precipitous decline to it's demise. National's Miami concentrated domestic structure didn't especially feed PA's international routes well; the NA/PA corporate cultures clashed, the merged fleets were incompatible, a recession began (again), and PA drastically overpaid for it. Though CEO William Sewell thought this merger would be a watershed for Pan Am, it ultimately meant the destruction of two legendary American carriers.