What terminal is American at Ontario airport ?


American Airlines uses Terminal 4 at Ontario International Airport (ONT). Terminal 4 is located on the east side of the airport, and it is connected to Terminal 2 by a free shuttle service.
Here are the contact details for American Airlines at Ontario International Airport:
Ticket Counter: Terminal 4, 2900 E. Airport Drive, Ontario, CA 91761
Phone: (800) 433-7300
Hours: Monday, Thursday, Friday, Saturday, Sunday: 4 a.m. – 4:45 p.m.; 7:30 p.m. – 11:30 p.m. Tuesday: 4 a.m. – 1:30 p.m.; 7:30 p.m. – 12:30 a.m. Wednesday: 4 a.m. – 4:45 p.m.; 7:30 p.m. – 12:30 a.m.