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$145+ Cheap flights from Louisville to Ontario (SDF - ONT)

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 11/24. Fares are subject to change and may not be available on all flights or dates of travel.
SDF — ONT
Nov 27 — Dec 41
Thu 11/27
Thu 12/4
1 adult, Economy
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Cheap flight deals from Louisville to Ontario

Discover tips and strategies to find the most affordable flight options for your journey from Louisville (SDF) to Ontario (ONT). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated October 28, 2025.

Most accurate provider

eDreams
3 stars

Most trusted provider

eDreams
3 stars

Round-trip from

$311
(Delta)

One-way from

$145
(United Airlines)

Popular in

January

Cheapest in

September

Average price

$403
Provider with most accurate pricing for Louisville Intl-Ontario flight deals.
Search Deals
Provider most trusted by Cheapflights users for Louisville Intl-Ontario flights.
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From Louisville Intl to Ontario
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One-way flight from Louisville Intl to Ontario
Search Deals
Highest demand for flights based on searches. 31% potential increase in price ($221 potential increase over avg. RT price).
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Cheapest flight prices on average. 12% potential price decrease ($54 potential savings vs. average RT price).
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Average for round-trip flights in October 2025
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Find flight deals from Louisville to Ontario

Cheapest flights from Louisville to Ontario
Explore the most affordable flight options available from Louisville to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on October 28, 2025.

This Delta deal was found by Cheapflights users on 10/26. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/2712:57 pmSDF - ONT
1 stop9h 45mDelta
Thu 12/410:25 pmONT - SDF
1 stop8h 25mDelta
Deal found 10/26$311
This Delta deal was found by Cheapflights users on 10/27. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/86:16 pmSDF - ONT
1 stop7h 48mDelta
Wed 12/1010:25 pmONT - SDF
1 stop8h 25mDelta
Deal found 10/27$321
This Delta deal was found by Cheapflights users on 10/26. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/103:18 pmSDF - ONT
2 stops11h 40mDelta
Wed 12/177:05 amONT - SDF
1 stop7h 11mDelta
Deal found 10/26$326
This Delta deal was found by Cheapflights users on 10/27. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/176:16 pmSDF - ONT
1 stop7h 48mDelta
Tue 11/1812:16 pmONT - SDF
1 stop6h 15mDelta
Deal found 10/27$432
This United Airlines deal was found by Cheapflights users on 10/26. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/278:00 amSDF - ONT
2 stops12h 34mUnited Airlines
Thu 12/45:05 amONT - SDF
1 stop6h 25mUnited Airlines
Deal found 10/26$453
This Delta deal was found by Cheapflights users on 10/27. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/117:05 amSDF - ONT
1 stop7h 01mDelta
Wed 11/1910:25 pmONT - SDF
1 stop8h 27mDelta
Deal found 10/27$462
This United Airlines deal was found by Cheapflights users on 10/26. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/258:00 amSDF - ONT
1 stop7h 33mUnited Airlines
Tue 12/25:05 amONT - SDF
1 stop6h 25mUnited Airlines
Deal found 10/26$492
This Delta deal was found by Cheapflights users on 10/27. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/177:05 amSDF - ONT
1 stop7h 01mDelta
Mon 11/1710:25 pmONT - SDF
1 stop8h 27mDelta
Deal found 10/27$497
This United Airlines deal was found by Cheapflights users on 10/28. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/319:05 amSDF - ONT
1 stop16h 20mUnited Airlines
Tue 1/61:24 pmONT - SDF
1 stop6h 20mUnited Airlines
Deal found 10/28$526
This United Airlines deal was found by Cheapflights users on 10/28. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/296:11 pmSDF - ONT
1 stop7h 14mUnited Airlines
Sun 1/411:59 pmONT - SDF
1 stop7h 04mUnited Airlines
Deal found 10/28$527
This United Airlines deal was found by Cheapflights users on 10/25. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/259:05 amSDF - ONT
1 stop16h 20mUnited Airlines
Tue 12/305:05 amONT - SDF
1 stop6h 17mUnited Airlines
Deal found 10/25$528

Cheapflights Fare Finder

 
Customize your flight search to find flights from Louisville to Ontario that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated October 28, 2025.
Use the filters below to find and compare flights from Louisville to Ontario that are best for you.

Fly from

Louisville

Fly to

Ontario

Route

Depart

Return

Price

LouisvilleOntario

SDF - ONT

SDFONT

Louisville Intl

Thu 11/27

12:57 pm-7:42 pm

1 stop9h 45m

Ontario

Thu 12/4

10:25 pm-9:50 am

1 stop8h 25m

$311

LouisvilleOntario

SDF - ONT

SDFONT

Louisville Intl

Thu 1/22

9:00 am-5:43 pm

2 stops11h 43m

Ontario

Sun 1/25

5:05 am-2:26 pm

1 stop6h 21m

$418

LouisvilleOntario

SDF - ONT

SDFONT

Louisville Intl

Sun 2/1

9:00 am-12:47 pm

1 stop6h 47m

Ontario

Sat 2/7

5:05 am-8:28 pm

2 stops12h 23m

$420

LouisvilleOntario

SDF - ONT

SDFONT

Louisville Intl

Thu 2/19

3:15 pm-8:50 pm

1 stop8h 35m

Ontario

Tue 2/24

6:00 am-8:14 pm

2 stops11h 14m

$428

LouisvilleOntario

SDF - ONT

SDFONT

Louisville Intl

Mon 11/17

7:05 am-11:06 am

1 stop7h 01m

Ontario

Wed 11/19

10:25 pm-9:52 am

1 stop8h 27m

$432

LouisvilleOntario

SDF - ONT

SDFONT

Louisville Intl

Mon 11/17

6:16 pm-11:04 pm

1 stop7h 48m

Ontario

Tue 11/18

12:16 pm-9:31 pm

1 stop6h 15m

$432

LouisvilleOntario

SDF - ONT

SDFONT

Louisville Intl

Tue 4/14

12:40 pm-6:15 pm

1 stop8h 35m

Ontario

Wed 4/15

12:00 pm-10:32 pm

1 stop7h 32m

$437

LouisvilleOntario

SDF - ONT

SDFONT

Louisville Intl

Tue 4/14

7:30 am-3:18 pm

2 stops10h 48m

Ontario

Wed 4/15

1:00 pm-9:57 pm

1 stop5h 57m

$442

LouisvilleOntario

SDF - ONT

SDFONT

Louisville Intl

Tue 3/10

10:15 am-4:19 pm

2 stops9h 04m

Ontario

Mon 3/16

10:30 pm-9:34 am

1 stop8h 04m

$442

LouisvilleOntario

SDF - ONT

SDFONT

Louisville Intl

Mon 11/24

3:20 pm-8:44 pm

1 stop8h 24m

$150

Flights are sorted by cheapest round-trip flights first.

Deals found on 10/26

Showing 1-10 of 16 results
1
2

Compare providers for flights from Louisville to Ontario

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.
Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Louisville to Ontario in October.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy2 starsTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*1 star
eDreamsPrice Accuracy3 starsTrust Score*3 stars

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

  • Most accurate provider: When it comes to deals on Louisville-Ontario flights, users find the pricing of eDreams to be most consistent on Cheapflights vs. eDreams Users can find the same prices on Louisville-Ontario flight deals on Cheapflights vs. eDreams >95% of the time. Price accuracy is based on data collected from Louisville-Ontario flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Louisville-Ontario flights, Cheapflights users trust eDreams the most. eDreams has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Louisville-Ontario flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

Best time to book a flight from Louisville to Ontario

Have a flexible travel schedule? Discover the best time to fly to Ontario from Louisville with our price prediction graph.
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

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

What is the cheapest month to book a flight from Louisville to Ontario?

Currently, May is the cheapest month in which you can book a flight from Louisville to Ontario (average of $93). Flying from Louisville to Ontario in April is currently the most expensive (average of $166). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

What is the cheapest time of day to fly from SDF to ONT?

Find hourly flight availability from Louisville to Ontario. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated October 28, 2025.

When flying from Louisville to Ontario, the time of day you fly usually plays a role in the price. Save by searching for a flight in the evening, which can drop the price by up to 37% versus a flight at noon.

Reviews of airlines servicing Ontario

Get insights into the airlines that provide service to Ontario. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Ontario. Reviews last updated October 28, 2025.
Get a feel of what it's like to fly with Southwest, Delta, and United Airlines from Louisville to Ontario by reading reviews from past customers. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.0
Very good
4,240 reviews

Crew

8.6

Boarding

8.1

Overall

8.0

Comfort

8.0

Food

7.0

Entertainment

7.5

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Southwest
8.0
Very good
4,240 reviews
Southwest
8.0
Very good
4,240 reviews

Crew

8.6

Boarding

8.1

Overall

8.0

Comfort

8.0

Food

7.0

Entertainment

7.5

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Delta
7.9
Good
7,994 reviews
Southwest
8.0
Very good
4,240 reviews

Crew

8.6

Boarding

8.1

Overall

8.0

Comfort

8.0

Food

7.0

Entertainment

7.5

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
United Airlines
7.4
Good
9,001 reviews
Southwest
8.0
Very good
4,240 reviews

Crew

8.6

Boarding

8.1

Overall

8.0

Comfort

8.0

Food

7.0

Entertainment

7.5

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
American Airlines
7.2
Good
11,032 reviews
Southwest
8.0
Very good
4,240 reviews

Crew

8.6

Boarding

8.1

Overall

8.0

Comfort

8.0

Food

7.0

Entertainment

7.5

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.

Related info for your journey

Find useful and relevant information for your journey from Louisville to Ontario. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • How long is the flight from Louisville to Ontario?

    Delta and United Airlines can get you from Louisville to Ontario in just under 9h 45m. Your travel time can differ by up to 1h 58m. Airlines will cover a distance of 1791 mi. Both multi-stop and nonstop flights can be found to your destination and back.

  • What are the cheapest airlines flying from Louisville to Ontario round-trip?

    American Airlines, at $268, was found to be the cheapest airline from Louisville to Ontario.Alternate airlines to your destination round-trip include Delta and Southwest. American Airlines is currently priced 45% below the average price you’ll pay for this route.

  • Can I find deals for flights from Louisville to Ontario that include hotel bookings?

    Yes. In addition to deals on Louisville to Ontario flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Louisville to Ontario?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Louisville to Ontario.

  • Can I find deals for business class flights from Louisville to Ontario?

    Yes. Cheapflights offers flight deals from Louisville to Ontario by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Louisville to Ontario?

    Currently, May is the cheapest month in which you can book a flight from Louisville to Ontario (average of $93). Flying from Louisville to Ontario in April is currently the most expensive (average of $166). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

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Top 4 airlines flying from Louisville to Ontario

Discover the top 4 airlines that operate flights from Louisville to Ontario. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated October 28, 2025.
AirlineCheapestAverageFlexibilityOn-time
American AirlinesCheapest$268Average$447FlexibilityNo cancel feeOn-time71%
DeltaCheapest$288Average$403FlexibilityNo cancel feeOn-timeN/A
SouthwestCheapest$306Average$402FlexibilityNo cancel feeOn-time63%
United AirlinesCheapest$344Average$606FlexibilityNo cancel feeOn-time69%

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