ONT - MKE

$158 Find Cheap Flights from Ontario to Milwaukee

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Ontario to Milwaukee departing on 3/4. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
1 adult, Economy, 0 bags

KAYAK searches hundreds of travel sites at once for deals on flights to Milwaukee

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Ontario to Milwaukee, as well as popular online travel agencies
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Ontario to Milwaukee, as well as popular online travel agencies
Travelers love KAYAK
41,299,237 searches in the past 7 days on KAYAK

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Everything you should know

Cheapest round-trip
$230
Overall average: $404
Frontier
Mon 3/9Mon 3/16
ONT - MKE • 1 stop
Cheapest one-way
$158
Typical prices: $122-$279
Delta
Wed 3/4
ONT - MKE • 1 stop
Top airlines
Frontier
Cheapest • from $230 (round-trip)
Southwest
Best reviews • 8.0 score
Airline reviews
Airline reviews
+1
+1
Airline reviews
Airline reviews
+1
When to travel
September
Cheapest • 19% price drop
June
Most popular
Good to know
Good to know
+1
+1
Good to know
Good to know
+1
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KAYAK searches 100s of sites at once to find you the best travel deals.
We hope you love your trip to Milwaukee!
Flight Deals
Booking Insights
Flight Deals

Cheap Flights from Ontario to Milwaukee (ONT-MKE)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Ontario to Milwaukee that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from Ontario to Milwaukee

Mon, Mar 9 - Mon, Mar 16
Frontier Logo
6:15 am - 6:51 pm
ONT
-
MKE
10h 36m
1 stop
Frontier Logo
7:15 pm - 11:59 pm
MKE
-
ONT
6h 44m
1 stop
$230Frontier
Fri, Mar 27 - Tue, Mar 31
Frontier Logo
6:15 am - 6:51 pm
ONT
-
MKE
10h 36m
1 stop
Frontier Logo
1:57 pm - 3:57 pm
MKE
-
ONT
28h 00m
1 stop
$308Frontier
Thu, Apr 9 - Sun, Apr 12
Delta Logo
1:20 pm - 9:25 pm
ONT
-
MKE
6h 05m
1 stop
Delta Logo
7:20 am - 12:23 pm
MKE
-
ONT
7h 03m
1 stop
$315Delta
Wed, Feb 18 - Sat, Feb 21
American Airlines Logo
7:05 pm - 7:49 am
ONT
-
MKE
10h 44m
2 stops
American Airlines Logo
3:11 pm - 10:49 pm
MKE
-
ONT
9h 38m
1 stop
$320American Airlines
Thu, Feb 12 - Sun, Feb 15
United Airlines Logo
5:00 am - 2:57 pm
ONT
-
MKE
7h 57m
1 stop
United Airlines Logo
8:28 am - 12:43 pm
MKE
-
ONT
6h 15m
1 stop
$326United Airlines
Thu, Feb 12 - Sun, Feb 15
United Airlines Logo
5:00 am - 5:31 pm
ONT
-
MKE
10h 31m
2 stops
United Airlines Logo
8:28 am - 12:43 pm
MKE
-
ONT
6h 15m
1 stop
$331United Airlines
Sat, Feb 14 - Wed, Feb 18
Alaska Airlines Logo
6:14 am - 2:51 pm
ONT
-
MKE
30h 37m
1 stop
Alaska Airlines Logo
3:47 pm - 10:44 pm
MKE
-
ONT
8h 57m
1 stop
$333Alaska Airlines
Fri, May 1 - Tue, May 12
American Airlines Logo
7:35 pm - 7:45 am
ONT
-
MKE
10h 10m
2 stops
American Airlines Logo
11:23 am - 8:27 pm
MKE
-
ONT
11h 04m
1 stop
$336American Airlines
Thu, Feb 12 - Sun, Feb 15
United Airlines Logo
5:00 am - 5:31 pm
ONT
-
MKE
10h 31m
2 stops
United Airlines Logo
6:00 am - 12:43 pm
MKE
-
ONT
8h 43m
2 stops
$337United Airlines
Fri, May 1 - Tue, May 12
American Airlines Logo
7:35 pm - 7:45 am
ONT
-
MKE
10h 10m
2 stops
American Airlines Logo
8:15 am - 6:24 pm
MKE
-
ONT
12h 09m
2 stops
$341American Airlines
Booking Insights

KAYAK's insights & trends for Ontario to Milwaukee flights

Get data-powered insights and trends into flights from Ontario to Milwaukee to help you find the cheapest flights, the best time to fly and much more.

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

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Ontario to Milwaukee, removes the top 0.1% to account for outliers, and then takes the median of all values for each month.

The cheapest month for flights from Ontario to Milwaukee is September, where tickets cost $366 (return) on average. On the other hand, the most expensive months are January and July, where the average cost of round-trip tickets is $846 and $487 respectively.

Good to know

Low seasonJanuary
Cheapest flight$158
Best time to beat the crowds but there is an average 86% increase in price.
Most popular time to fly and prices are also 6% lower on average.
Flight from Ontario to Milwaukee

When to book flights from Ontario to Milwaukee

Are your dates flexible? Find out the best times to travel from Ontario to Milwaukee based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price
KAYAK looks at all historical flight data for each date to provide a predicted price for one-way trips or round-trips with a duration up to 40 days. While we try to provide actual minimum prices for each date, some prices are predictions and actual prices may differ.

FAQs for booking flights from Ontario to Milwaukee

  • What is the cheapest flight from Ontario to Milwaukee?

    In the last 3 days, the lowest price for a flight from Ontario to Milwaukee was $158 for a one-way ticket and $230 for a round-trip.

  • Do I need a passport to fly between Ontario and Milwaukee?

    A passport is not required to fly from Ontario to Milwaukee.

  • Which aircraft models fly most regularly from Ontario to Milwaukee?

    We unfortunately don’t have that data for this specific route.

  • Which airline alliances offer flights from Ontario to Milwaukee?

    SkyTeam, Star Alliance, and oneworld are the airline alliances operating flights between Ontario and Milwaukee, with SkyTeam being the most commonly used for this route.

  • Which is the best airline for flights from Ontario to Milwaukee, Southwest or Delta?

    The two airlines most popular with KAYAK users for flights from Ontario to Milwaukee are Southwest and Delta. With an average price for the route of $419 and an overall rating of 8.0, Southwest is the most popular choice. Delta is also a great choice for the route, with an average price of $391 and an overall rating of 7.9.

  • How does KAYAK find such low prices on flights from Ontario to Milwaukee?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Ontario to Milwaukee.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Ontario to Milwaukee?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to Milwaukee from Ontario is likely to change within 7 days, so travelers know whether to wait or book now.

  • What is the Hacker Fare option on flights from Ontario to Milwaukee?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly to Milwaukee with an airline and back to Ontario with another airline. Booking your flights between Ontario and MKE can sometimes prove cheaper using this method.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Ontario to Milwaukee?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying to Milwaukee from Ontario up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

Reviews of the top 4 airlines serving from Ontario to Milwaukee

 
See real verified KAYAK customer reviews for airlines flying from Ontario to Milwaukee. Airline scores are aggregated from all reviews left by passengers on KAYAK after flying with an airline. KAYAK doesn’t show reviews that are older than 5 years. Learn how KAYAK collects reviews.
Need help choosing which airline to fly with from Ontario to Milwaukee? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
8.0
SouthwestOverall score based on 4261 reviews
7.5Entertainment
7.0Food
8.6Crew
8.0Comfort
8.1Boarding
Airline reviews

3 hour delay. Had to change plans and was still delayed.

2.0 MediocreAnonymous, Jan 2026
SFO - SAN
Read more Southwest reviews

3 hour delay. Had to change plans and was still delayed.

We got exit row seats both flights. Everything was running on time

The boarding and seat assignment system no longer works for me, but I know it is being replaced. Otherwise, I am good with the overall experience.

The lead steward kept singing about "San Francisco" and hotel California---more annoying than humorous....needs work. Flight was smooth and on time.

San Diego airport is brand new, spacious, airy and very smooth checkin at SW baggage drop.

Crew could have been friendlier, maybe I'm spoiled by SW crews. In flight wifi was good. Would be nice to have more food offerings on a 4 plus hour flight

Ever since Southwest starting charging for bags, passengers don't want to pay to check their bags, so the gate agents have to beg people to check their roller bags now because there's "not enough space". This was a terrible business move by Southwest.

Sacrament staff are always polite and helpful. Airport is easy to maneuver and boarding is straightforward.

As always, the entire Southwest experience was wonderful, from online booking to flight to baggage retrieval. Very grateful.

The weather could have been better. There was a 40 minute ATC delay in SFO because of marine fog and a micro cell storm delayed landing and take-off at Nashville. The gate was changed 5 minutes from boarding from gate B3 to gate C23 at Nashville airport.

Delta’s staff is unmatched. From the gate agents, to the pilots, to the flight attendants… all top of the industry.

The flight was delayed for about 2 hrs. Other than it, it was good.

I am extremely disappointed that delta internal pilot manuals now refer to the Gulf of Mexico as the “gulf of America”. You can bow down to the Orange turd on your own. I will never fly delta again

My flight was cancelled with no explanation after I had already cleared security. I was given 4 options to rebook, only one being non-stop like I had paid for. I grabbed it. It was 4 plus hours later and then took off even later. Biggest complaint is that I booked early and had an aisle seat. They gave me a "window" seat in front of the exit row, so the seat did not decline. I weigh all of 103 #s and it was tight for me! For what I paid, I feel I was kind of ripped off. I think they should have given me the empty comfort seat for the inconvenience. There was no apology nor any explanation as to why the flight was cancelled. My guess is it benefitted Delta in some way.

No lunch on a x-country flight scheduled for 10:50 am departure, arrived 5+ hrs later. That requires a black box label before you pay for the tickets. Worst, when I checked in online, it's specifically said that lunch was served on his flight for economy Plus passengers.

Our flight from SFO to MSP was right on time on 11/15/2025. No delays. As we approached MSP at about 8 pm, we circled in the air until 8:40 pm so I don't call that efficient for MSP. I think the captain should announce the delay and why. (as if we all don't know that we are just circling around the area, slowing down, speeding up, slowing down.) Thank you. Marilyn Fischer

Staff were friendly and happy. Delta could make sure passengers that don't have the app know of changes. Without Kayak I would not have known about the change of gate or the delay. Kayak was faster to notify me.

The flight used a B767 with a very old interior from before 2014. The entertainment system did not work at all during the flight despite attempts to reset the system. It was like they flew this route just to be competitive.

Delayed flight (1hour) plus a long layover after an overnight flight with no backup plane available.

Flight delayed for two and half hours and then canceled altogether due to mechanical issues. No mechanic onsite to fix so had to send one from LAX.

The flight crew where really good. Better then the crew from BNE to SFO

left on time, reasonable boarding process arrived early luggage came out quickly

I’m so sorry, I can’t remember her name, I believe it was Dimpti. She was stellar, also a mature Asian flight attendant, lots of flowers in her hair, just as amazing! But literally the crew was AWESOME . Only downside is there weren’t any charging outlets. Maybe I needed to ask a flight attendant , but it would’ve been nice to have one easily accessible.

I boarded flight UA#1318 at Sacramento International Airport going back to Houston TX. The flight was scheduled at 5:10am. I was able to check in virtually using the United Airlines app. When I entered the airport, there was no one outside assisting with checked bags as it was for Delta Airlines. Immediately upon entering, there was a LONG, EXTREMELY LONG line to the kiosks to get boarding passes. I stand in line to get boarding passes then had to move to ANOTHER EXTREMELY LONG line to get my bags checked in. While standing in this line, we noticed an agent taking customers to 3 at a time to her station to check their bags in. Lucky for me, she called me back, checked my bags for me and I was on my way. I then encountered another long line at the TSA check and to avoid I ending up having to sign up for CLEAR to bypass it. So glad, I did.,...Both of my flights were great with no issues, butthe check in progress at Bush Airport was so much smoother. Check-in at SMF airport needs to be anaylzed and corrected. Do better United, I know you can....thanks

Pushed back only to get deplaned due to a tire damaged by ground crew. They did at least go pretty fast. The bathrooms should be banned under the Geneva convention. No room to even sit straight on the toilet. The under-seat entertainment units block what little leg room there is.

United airlines has the best customer experience from booking to arrival. I always fly United airlines. The mileage program is excellent

Older aircraft, no meal, only food was for purchase. Not impressed United.

Not pleasant trip cross country when the entertainment and WiFi system not working. No entertainment for entirety of route. Staff was rather nonchalant in that they dismissed the problem due to age of plane. It would have been nice to know this up front so I could have come prepared to read or download movies before boarding Coincidentally or not, there was a similar issue with the entertainment system on my previous flight I took on my fist leg of the trip. There are no seat TVs, so you must rely on the app when it works. United can do better. Also, what use it it to pay for boarding group 2 when half of the passengers are in the same line as you?

Premium Plus is a really good idea for longer flights

The flight attendants were great, I joked with one I can’t remember her name, a blond, really sweet. I thought it was run well very professional. This was great i survived Spirit, I know for which I speak.

We were upgraded to First Class and it was a great flight

The flight was on time and arrived early. The crew were friendly and helpful.

Overall experience was great. Flights were almost on time in departing and we arrived at our destination as scheduled. No issues with amenities or flight crew. Everything went well as as expected. Will fly again with American Airlines in the future!

it was fine, decent flight... dont get food besides cookies or pretzels so not sure why you ask about food. same for entertainment..

Horrible. Both legs of my flight were delayed more than 6 hours. No compensation, no screens on the plane, and the plane was not clean.

this plane was really old, had exit row seats and tray was in arm of seat so super uncomfortable to use. another seat they could t even use the tray it was broke. seat i. front of me had duct tape on it cause seat was ripped open... this plane should either be updated or retired.

We loved the steward on the plane. He made the night enjoyable

The flight was smooth, the pilot kept us informed about delays and we arrived more of less on time

The flight was flawless and we even arrived between 20 and 25 minutes early!

Always seated jammed in rear of aircraft Admirals Club food at DFW terminal D was absolute worst food experience and I pay $600/year to eat this dried out junk

Everything you need to know for your flight from Ontario to Milwaukee

Information on your arrival and departure airports