St. Louis, MO STL to Ontario, CA ONT Flights

The earliest flight from St. Louis, MO to Ontario, CA leaves at 5: 00AM. Plan your trip with the Journey Planner   from Omio.

The latest flight from St. Louis, MO to Ontario, CA leaves at 11: 35PM.

It's helpful to compare your options as there are 2 ways to travel to Ontario, CA from St. Louis, MO including taking a train or bus.

Since neither St. Louis, MO nor Ontario, CA are in the Schengen Area, passport requirements depend on the specific immigration rules of USA and USA. Entry and visa requirements can be subject to change. For the latest information, check with your destination's embassy or consulate.

There is a time difference of 2 h between St. Louis, MO and Ontario, CA all year round.

The best events to attend in Ontario, CA include:

• California Citrus State Historic Park Festival, celebrate the citrus industry with local vendors and activities
• Ontario International Airport Airshow, witness thrilling aerial performances and displays
• Ontario Harvest Festival, a community celebration featuring local produce and crafts
• Chaffey Community Museum of Art Annual Fundraiser, support local art through exhibitions and auctions.

The best holidays to experience in Ontario, CA include:

• New Year's Day, mild winter weather and fresh beginnings
• Memorial Day, kick-off to summer with outdoor activities
• Independence Day, patriotic celebrations and fireworks
• Labor Day, end of summer festivities and community events
• Thanksgiving, a time for family gatherings and seasonal harvest celebrations.

The best seasons to visit Ontario, CA are Spring or Fall. The best weather to explore Ontario, CA is during April-June or September-November.

For domestic flights we recommend to arrive 1.5 to 2 hours before departure. Please check the website of your departure airport if in doubt. Some airports may offer booking time slots for security checks or offer additional information on when to get there based on time of day.

Most airlines permit carry-on bags that fit within specific dimensions (e. G. 22 x 14 x 9 inches or 56 x 36 x 23 cm), including handles and wheels. Bags must fit in the overhead bin or under the seat in front of you.

Many airlines impose weight limits, commonly ranging between 7 kg (15 lbs) and 12 kg (26 lbs).
Typically, passengers are allowed one carry-on bag and one personal item (for example a purse, laptop bag, or backpack). Personal items must fit under the seat in front of you.
Budget Airlines (like Ryanair or Wizz Air) have stricter size and weight limits, often requiring fees for larger carry-ons. Full-Service Airlines have more lenient policies, sometimes including more spacious dimensions or higher weight limits depending on your ticket class.

The list of items prohibited on an airplane varies by country and airline, but in general, the following items are not allowed in carry-on or checked baggage: Weapons and self-defence items, sharp objects, flammable materials, explosives, toxic substances, or liquids over 100ml (except for medications and baby essentials). In checked baggage, firearms (without authorization), explosives, large lithium batteries, and hazardous chemicals are prohibited. Electronic cigarettes must be in carry-on bags, while alcohol and dry ice have restrictions. Always check with your airline for specific regulations.