Cheap Flights From Ontario (ONT) | 2026 Deals, Routes & Tips

Finding Cheap Flights From Ontario

Ontario is served by Ontario International Airport (ONT), a major airport in the Inland Empire region of Southern California. It has grown as a key alternative to Los Angeles International (LAX), focusing on domestic and international leisure travel, with a strong presence from low-cost and ultra-low-cost carriers.

The airport provides extensive domestic connectivity to major hubs and popular cities across the United States, including Seattle, Denver, Dallas, Chicago, and Atlanta. It also offers a significant number of flights to Mexico and seasonal services to other international destinations. Key routes include high-frequency services to the Pacific Northwest and the Southwest.

Ontario International is a major base for Southwest Airlines and sees significant operations from American Airlines and Delta Air Lines. Ultra-low-cost carriers Spirit Airlines and Frontier Airlines have a strong presence. International carriers like Volaris and Aeroméxico provide service to Mexico.

To find cheap flights from Ontario, book domestic flights 1-2 months in advance, using Southwest for value or Spirit/Frontier for low base fares (plus fees). For international travel to Mexico, book 2-3 months ahead. Use flight comparison tools. Flying on weekdays (Tuesday-Thursday) is significantly cheaper. ONT is known for having lower fares and less congestion than LAX for many domestic routes. For a wider selection of long-haul international flights, LAX is still necessary, but Ontario excels for convenient, affordable travel within North America.