Cheap flights from Ontario to Chicago

One-way fares from $82 · ONT → CHI · prices found by travellers in the last 48 hours

Compare all dates Chicago → Ontario
Cheapest fare
$82

Frontier Airlines · Wed, Dec 2

Cheapest month
December

from $82

Direct flights
Not recently

Usually 1+ stop

Quickest trip
4h 30m

2,750 km

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Cheapest month to fly from Ontario to Chicago

Lowest one-way fare per person in each month. Choose a month to see every date.

  1. November 2026 $91
  2. December 2026 Cheapest $82
  3. January 2027 $105
  4. March 2027 $105
  5. April 2027 $145
  6. September 2027 $167

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About flights from Ontario to Chicago

Ontario (ONT) and Chicago (CHI) are about 2,750 km apart. We haven't seen direct fares on this route recently, so expect at least one stop; the quickest journey we've seen takes about 4h 30m. Over the next few months, one-way fares start from $82, and December 2026 is currently the cheapest month to fly.

These prices come from searches travellers made in the last 48 hours, so they move quickly. If you see a good fare, it's worth booking soon. FlightsExp is free to use: you book directly with our travel partner.

Frequently asked questions

How much is a flight from Ontario to Chicago?

The cheapest one-way fare we've seen recently is $82 with Frontier Airlines, departing Wednesday, December 2, 2026. Over the coming months, the lowest fare in each month ranges from $82 to $167.

What is the cheapest month to fly from Ontario to Chicago?

December 2026 currently has the lowest fares, from $82 one way.

Are there direct flights from Ontario to Chicago?

We haven't seen direct fares recently, so most journeys include at least one stop.

How long is the flight from Ontario to Chicago?

The quickest journey we've seen takes about 4h 30m. Ontario and Chicago are around 2,750 km apart.

Which airlines fly from Ontario to Chicago?

Recent fares on this route were with Frontier Airlines, Southwest Airlines and Alaska Airlines.

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