Ontario International Airport
Ontario, United StatesONT / KONT
Major airport · 63 direct destinations · 2 runways · longest runway 12,198 ft
79 °F · ClearSource: METAR observation via the NOAA Aviation Weather Center
Route
Ontario → Denver
ONT
OntarioOntario International Airport
OntarioOntario International AirportDENDenverDenver International Airport
DenverDenver International Airport- Distance
- 818 mi
- Estimated flight time
- ~2h 10m
Denver is currently 1 hour ahead of Ontario.
Observed nonstop
How often does this route fly?
Frequency
Several times a day
On average around 8 flights a day, observed from October 2025 to September 2026.
- 8
- flights per day
- 9
- busiest month · Oct
- 7
- quietest month · Jan
- 1 hr 47 min
- measured flight time
- 12 / 12
- months seen
Through the year
Per day, month by month
- 7Jan2026
- 7.5Feb
- 7Mar
- 7.5Apr
- 8May
- 9Jun
- 9Jul
- 8Aug
- 9Sep
- 9Oct2025
- 9Nov
- 8Dec
Airlines
Who flies it
Southwest Airlinesall year
United Airlinesall year
Frontier Airlinesall year
UPS Airlinesall year
Air Transport Internationalwinter
Through the day
Departure times
Local time in Ontario. Most departures between 05:00 and 08:00.
- 00:00
- 01:00
- 02:00
- 03:00
- 04:00
- 05:00
- 06:00
- 07:00
- 08:00
- 09:00
- 10:00
- 11:00
- 12:00
- 13:00
- 14:00
- 15:00
- 16:00
- 17:00
- 18:00
- 19:00
- 20:00
- 21:00
- 22:00
- 23:00
Through the week
By weekday
- 7.8Mon
- 8.8Tue
- 8.5Wed
- 9.5Thu
- 8.6Fri
- 7Sat
- 7.3Sun
Fleet
Aircraft observed
- Boeing 737-800B73822%
- Boeing 737 MAX 8B38M18%
- Airbus A320neoA20N10%
- Boeing 767-300B7639%
- Boeing 737-700B7379%
All the numbers in a table
| Month | Per day | Seen | Airlines |
|---|---|---|---|
| January 2026 | 7 | 229 |
|
| February 2026 | 7.5 | 217 |
|
| March 2026 | 7 | 230 |
|
| April 2026 | 7.5 | 217 |
|
| May 2026 | 8 | 230 |
|
| June 2026 | 9 | 271 |
|
| July 2026 | 9 | 270 |
|
| August 2026 | 8 | 238 |
|
| September 2026 | 9 | 255 |
|
| October 2025 | 9 | 295 |
|
| November 2025 | 9 | 276 |
|
| December 2025 | 8 | 245 |
|
Airlines observed on this route
From observed callsign routes on ONT-DEN - not a booking guarantee.
About this route
- Domestic route: both airports are in the same country.
- The opposite direction has also been observed as a direct connection.
- Direct destinations observed from Ontario: 63.
- Direct destinations observed from Denver: 203.
The airports on this route
Denver International Airport
Denver, United StatesDEN / KDEN
International hub · 203 direct destinations · 6 runways · longest runway 16,001 ft
36 °F · ClearSource: METAR observation via the NOAA Aviation Weather Center
Alternative airports for this journey
Same journey, a different airport nearby - with an observed direct connection.
SBD DENSan Bernardino International AirportSan Bernardino is about 21 mi from Ontario.View route →SNA DENJohn Wayne Orange County International AirportSanta Ana is about 30 mi from Ontario.View route →LGB DENLong Beach International AirportLong Beach is about 35 mi from Ontario.View route →BUR DENHollywood Burbank/Bob Hope AirportBurbank is about 45 mi from Ontario.View route →
About the route from Ontario to Denver
The observed direct connection between Ontario International Airport (ONT) and Denver International Airport (DEN) covers approximately 818 mi. The estimated flight time is around 2h 10m. Air Transport International, Frontier Airlines, Southwest Airlines, United Airlines and UPS Airlines have been observed on this connection in the available route data.
Frequently asked questions about this route
- How far is Ontario from Denver by air?
- The great-circle distance between Ontario International Airport and Denver International Airport is approximately 818 mi.
- How long is the flight from Ontario to Denver?
- Based on the distance, the estimated flight time is about 2h 10m. This is an estimate, not a schedule.
- Is there a direct connection from Ontario to Denver?
- Yes, a direct connection between ONT and DEN has been observed in our route data.
- Which airlines have been observed on this route?
- In the available route data: Air Transport International, Frontier Airlines, Southwest Airlines, United Airlines and UPS Airlines.
- How often is there a flight from Ontario to Denver?
- On average around 8 flights a day, measured over twelve months (October 2025 to September 2026) in the flight archive, with 2,973 observed flights. Mainly Southwest Airlines, United Airlines, Frontier Airlines. That is an observation, not a timetable.
- What is the current time difference between Ontario and Denver?
- Denver is currently 1 hour ahead of Ontario.
Where this data comes from
The route data comes from the flight archive (ADS-B, adsb.lol): which connections actually flew over the last twelve full months and who flew them, combined with our own airport, runway, and airline datasets. It is reference data about observed routes - not a current timetable and no claim about bookability.
The frequency and aircraft on this page come from the flight archive (ADS-B, 12 months, October 2025 to September 2026), summarized per route per month. We do not see every flight, so it is a floor, not a count.
Route data updated on October 11, 2026.