Here are all of the airlines that service ONT and their phone numbers!
Alaska Airlines – (800) 252-7522
American Airlines – (800) 433-7300
Avianca - (800) 284-2622
China Airlines – (800) 227-5118
Delta Air Lines- (800) 221-1212
Frontier Airlines - (800) 401-9000
Hawaiian Airlines - (800) 367-5320
JetBlue - (800) 538-2583
Southwest Airlines - (800) 435-9792
United Airlines - (800) 864-8331
Volaris - (855) 865-2747