ONT - SDF

$161 Find Cheap Flights from Ontario to Louisville

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 Louisville 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 Louisville

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

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Everything you should know

Cheapest round-trip
$321
Overall average: $418
United Airlines
Wed 4/8Wed 4/15
ONT - SDF • 1 stop
Cheapest one-way
$187
Typical prices: $171-$261
Multiple Airlines
Wed 3/4
ONT - SDF • 3 stops
Top airlines
United Airlines
Cheapest • from $321 (round-trip)
Southwest
Best reviews • 8.0 score
Airline reviews
Airline reviews
+1
+1
Airline reviews
Airline reviews
+1
When to travel
July
Cheapest • 20% price drop
September
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 Louisville!
Flight Deals
Booking Insights
Flight Deals

Cheap Flights from Ontario to Louisville (ONT-SDF)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Ontario to Louisville 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 Louisville

Wed, Apr 8 - Wed, Apr 15
United Airlines Logo
1:34 pm - 10:39 pm
ONT
-
SDF
6h 05m
1 stop
United Airlines Logo
3:30 pm - 9:50 pm
SDF
-
ONT
9h 20m
1 stop
$321United Airlines
Wed, Apr 8 - Wed, Apr 15
United Airlines Logo
1:34 pm - 10:39 pm
ONT
-
SDF
6h 05m
1 stop
United Airlines Logo
9:00 am - 5:47 pm
SDF
-
ONT
11h 47m
2 stops
$326United Airlines
Wed, Apr 8 - Wed, Apr 15
Southwest Logo
6:55 am - 8:35 pm
ONT
-
SDF
10h 40m
2 stops
Southwest Logo
3:30 pm - 9:30 pm
SDF
-
ONT
9h 00m
2 stops
$350Southwest
Mon, Mar 9 - Mon, Mar 16
American Airlines Logo
11:59 pm - 9:51 am
ONT
-
SDF
6h 52m
1 stop
American Airlines Logo
6:23 pm - 10:30 pm
SDF
-
ONT
7h 07m
1 stop
$359American Airlines
Tue, Mar 31 - Sun, Apr 5
United Airlines Logo
5:10 am - 2:31 pm
ONT
-
SDF
6h 21m
1 stop
United Airlines Logo
5:43 pm - 10:26 pm
SDF
-
ONT
7h 43m
1 stop
$379United Airlines
Tue, Mar 31 - Sun, Apr 5
American Airlines Logo
7:59 pm - 8:50 am
ONT
-
SDF
9h 51m
2 stops
American Airlines Logo
6:23 pm - 11:59 pm
SDF
-
ONT
8h 36m
1 stop
$384American Airlines
Tue, Mar 31 - Sun, Apr 5
Southwest Logo
9:45 pm - 10:30 am
ONT
-
SDF
9h 45m
2 stops
Southwest Logo
5:35 pm - 10:35 pm
SDF
-
ONT
8h 00m
2 stops
$389Southwest
Fri, Mar 13 - Mon, Mar 23
Southwest Logo
11:55 pm - 10:00 am
ONT
-
SDF
7h 05m
1 stop
Southwest Logo
8:35 am - 2:10 pm
SDF
-
ONT
8h 35m
1 stop
$398Southwest
Tue, May 12 - Sun, May 17
Southwest Logo
10:55 am - 10:30 pm
ONT
-
SDF
8h 35m
2 stops
Southwest Logo
6:20 pm - 12:05 am
SDF
-
ONT
8h 45m
2 stops
$399Southwest
Mon, Mar 16 - Tue, Mar 24
Delta Logo
10:25 pm - 9:28 am
ONT
-
SDF
8h 03m
1 stop
Delta Logo
7:05 am - 11:47 am
SDF
-
ONT
7h 42m
1 stop
$402Delta
Booking Insights

KAYAK's insights & trends for Ontario to Louisville flights

Get data-powered insights and trends into flights from Ontario to Louisville 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 Louisville?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Ontario to Louisville, 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 Louisville is July, where tickets cost $393 (return) on average. On the other hand, the most expensive months are January and November, where the average cost of round-trip tickets is $976 and $494 respectively.

Good to know

Low seasonJanuary
Cheapest flight$187
Best time to beat the crowds but there is an average 98% increase in price.
Most popular time to fly and prices are also 6% lower on average.
Flight from Ontario to Louisville

When to book flights from Ontario to Louisville

Are your dates flexible? Find out the best times to travel from Ontario to Louisville 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 Louisville

  • What is the cheapest flight from Ontario to Louisville?

    In the last 3 days, the lowest price for a flight from Ontario to Louisville was $187 for a one-way ticket and $321 for a round-trip.

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

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

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

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

  • Which airline alliances offer flights from Ontario to Louisville?

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

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

    The two airlines most popular with KAYAK users for flights from Ontario to Louisville are Southwest and Delta. With an average price for the route of $451 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 $466 and an overall rating of 7.9.

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

    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 Louisville.

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

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to Louisville 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 Louisville?

    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 Louisville with an airline and back to Ontario with another airline. Booking your flights between Ontario and SDF 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 Louisville?

    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 Louisville 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 Louisville

 
See real verified KAYAK customer reviews for airlines flying from Ontario to Louisville. 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 Louisville? 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 4286 reviews
8.1Boarding
8.0Comfort
8.6Crew
7.5Entertainment
7.0Food
Airline reviews

The charges were ridiculous for an hour flight and the turbulence was very scary.

2.0 MediocreDarcey, Feb 2026
SAN - SJC
Read more Southwest reviews

The charges were ridiculous for an hour flight and the turbulence was very scary.

The seats are now more narrow. I paid for front row the seats in the front are even more narrow than before.

The wifi on the plane is great. The only issue that I have is that I prefer an aisle seat and on my trips this week, I was either in the middle or window. If we can work to secure aisle seating, I will be thrilled. Nice trip.

Great flight but super high price. Glad it was a business trip and not personal

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

Everything I mentioned earlier - the airbus was more comfortable indeed and the experience was further enhanced.

The plane was an older model, so it wasn’t as comfortable as others. The flight attendants were not helpful during onboarding. It was a full flight so there was chaos finding space for baggage.

Awesome! On time flight, early arrival, and a complimentary upgrade!

Delta One is extraordinary. I fly business when somebody hires me. I just wonder why there is such a chasm between business class and the insanely inhumane and nonsensical coach. The seats are not large enough to fit even my tiny wife. We fly 10% of what we did because we don’t want to pay 5-10 k but for $400 it’s unbearable. It seems like the accountants took over and made stupid decisions. Screw in 20 extra seats and make it so unbearable that people fly 90% less. Just put the damn price up and put some proper chairs in. But business, yay.

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

Lady Pilot was perfect in every way wheels up to wheels down communication, professionalism, excellent on time departure and on time arrival, excellent communication! Fantastic job with Superb attitude!!

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

Very disappointing given gate agent behavior. Filed a formal complaint with United.

Crew was great (professional, attentive, prompt). Snacks for 4 hrs flight is deplorable.

Flight delayed. WiFi connectivity very poor if not existant. Last minute arrival forced me to run to catch my connection.

Terrible. No customer service, no food, no drinks on a 6 hour premier economy booking.

Short flight, but no drink/snack service. The flights both going and coming were delayed.

It was a pretty standard flight... until the almost hour and a half spent on the taxi way. I get that the weather has been poor but the delay had nothing to do with the weather and more to do with a plane with several issues tying up the gate. I get that that happens from time to time but this has been EVERY flight I've been on for the past 5 years and I fly 3 to 5 times a year. This isn't just United... it's American, it's Delta. It's an issue with the entire industry. I work for UPS and packages on a cargo plane get better service than people do these days. Anymore I HATE flying.

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

Flight was delayed for 2 hours, then last minute the change to on time. The satélite location is far and a nightmare to get to.

We flew in first class. The crew did not offer drinks before the flight took off, but they treated us well during the flight. The food was excellent. There was actually too much food served, but it was nice to have all the options.

For a 5 1/2 hour flite i considered the "business class" to be subpar. The seats were just ok, no amenities, really nothing more than a long domestic flight. Frankly disappointed.

It would be nice to have some low carb options in the snacks.

The entertainment options were at best, fair. It was exactly the same as my outbound flight. It would have been more entertaining if there were some series from Apple TV, HBO, Showtime or other carriers for me to catch up with.

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!

The boarding process needs to be fixed. The zone don't work, especially when there is hardly anyone in zones 3, 4,and 5, leaving the majority of the passengers backed up in the aisle, especially because passengers seated near the front are blocking passengers who are seated in the rear of the plane. It would also help if the size of carry on bags was more strictly enforced.

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.

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

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

Information on your arrival and departure airports