Cheap flights from Ontario to Chicago from $129 ONT → MDW, ORD

Found recently, and the cheapest we hold

What have prices looked like?

Over 49 days, 24 Sept to 11 Nov, the cheapest return we saw each day was $157 to $243.

At $302, the cheapest return found recently is above that range.

Those were the prices on those days, not today's.

Could nearby dates be cheaper?

No. We hold 4-night return fares on 2 other departure dates within 3 days of 30 Dec, and none is cheaper.

Every date we hold

200 fares on 14 departure dates

Which month looks cheapest?

December 2026 is the cheapest month — from $218.

Found recently, and the cheapest we hold

What have prices looked like?

Over 49 days, 24 Sept to 11 Nov, the cheapest one-way we saw each day was $76 to $133.

Those were the prices on those days, not today's.

Could nearby dates be cheaper?

We hold no other one-way fares leaving within 3 days of 11 Jan 2027 to compare.

Every date we hold

33 fares on 8 departure dates

Which month looks cheapest?

February 2027 is the cheapest month — from $119.

Return

Fares 14 to 29 days before departure were typically 20% lower than 0 to 6 days before departure.

From the cheapest return each day between 24 Sept and 11 Nov (49 days), grouped by how many days ahead the flight left; one adult in economy.

Each range covers different departure dates, so this compares typical fares, not the same trip priced twice.

Prices reflect recent searches — current fares may differ.

One-way

Fares 30 to 59 days before departure were typically 8% lower than 0 to 6 days before departure.

From the cheapest one-way each day between 24 Sept and 11 Nov (49 days), grouped by how many days ahead the flight left; one adult in economy.

Each range covers different departure dates, so this compares typical fares, not the same trip priced twice.

Prices reflect recent searches — current fares may differ.

How much is a return flight from Ontario to Chicago?

The cheapest return found recently is $302 with Frontier Airlines, 30 Dec to 3 Jan 2027, found 2 days ago. The cheapest return we hold, of any age, is $218 with Frontier Airlines, 11 Dec to 15 Dec, found 4 days ago. The cheapest return fare on each of 14 departure dates is usually $250 to $343.

How much is a one-way flight from Ontario to Chicago?

The cheapest one-way found recently is $129 with Frontier Airlines, 11 Jan 2027, found 2 days ago. The cheapest one-way we hold, of any age, is $119 with Southwest Airlines, 12 Feb 2027, found 7 days ago. The cheapest one-way fare on each of 8 departure dates is usually $127 to $168.

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

December 2026 is the cheapest month for a return, from $218, 11 Dec to 15 Dec, found 4 days ago. February 2027 is the cheapest month for a one-way, from $119, 12 Feb 2027, found 7 days ago.

Every date in December 2026

How far ahead should I book a flight from Ontario to Chicago?

In 49 days of prices between 24 Sept and 11 Nov, return fares 14 to 29 days before departure were typically 20% lower than 0 to 6 days before departure. One-way fares 30 to 59 days before departure were typically 8% lower than 0 to 6 days before departure.

Is there a direct flight from Ontario to Chicago?

Yes, the cheapest nonstop return found recently is $418 with Frontier Airlines, 30 Dec to 3 Jan 2027, found 2 days ago. The cheapest nonstop one-way found recently is $136 with Southwest Airlines, 17 Feb 2027, found 3 days ago.

Every nonstop date from Ontario to Chicago

How long is the flight from Ontario to Chicago?

The cheapest nonstop one-way found recently, with Southwest Airlines on 17 Feb 2027, takes 3 h 55 min from Ontario International Airport (ONT) to Chicago Midway International Airport (MDW). The cheapest one-way found recently, with Frontier Airlines on 11 Jan 2027, takes 11 h 32 min with 1 stop.

Which airlines have the cheapest flights from Ontario to Chicago?

Between 18 Nov and 19 Mar 2027, Frontier Airlines has the cheapest return on 9 of the 14 departure dates we hold, Southwest Airlines on 4 and American Airlines on 1. Between 17 Dec and 3 May 2027, Southwest Airlines has the cheapest one-way on 3 of the 8 departure dates we hold, Frontier Airlines on 3 and United Airlines on 1.