Route on-time record
LAS to ONT: most on-time flights and the best time to fly
Las Vegas (Harry Reid International Airport) to Ontario (Ontario International Airport). 2,484 nonstop flights in Jun 2025 to May 2026, 76% arrived within 15 minutes and 0.8% were cancelled. The most reliable flight number was Southwest 3341 at 7:15 AM.
Flying on a specific date? We’ll adjust for the month, the weekday and the forecast.
LAS → ONT
Las Vegas to Ontario: 2,484 nonstop flights a year
On time (12 months)
76%
Cancelled
0.8%
avg delay 14 min
Best time to leave
Before 9 AM
94% on time vs 59% after 9 PM
Most reliable airline
Frontier
80% chance on time
Lowest nonstop fare seen in the next two months: $51 (Frontier 1923 on 2026-11-03). Fares open on our travel partner (Aviasales). Pick the flight number you chose here.
Most reliable nonstop flights
Ranked by the chance the flight operates and arrives within 15 minutes of schedule, from Jun 2025 to May 2026 records.
#1 · Southwest 3341
7:15 AM → 8:20 AM1h 05m nonstop
Local times, typical schedule. Last flown 2026-05-31. Same departure also flew as Southwest 3606; its record covers all of them.
93%
chance on time
- On time (history)
- 97%
- Cancelled
- 0.0%
- Avg arrival delay
- 1 min
- Arrived on time 97% of the time (78 flights, Jun 2025 to May 2026).
- Never cancelled in 78 scheduled flights.
- Leaves in this route's most on-time window (Before 9 AM: 94% on time; After 9 PM: 59%).
- Departs outside LAS's trouble window (10 AM to 4 PM, when 51% of its 104 ground stops and delay programs started).
Moderate track record · 78 flights
Find Southwest 3341 fares Opens this date on Aviasales#2 · Frontier 1283
7:00 AM → 8:04 AM1h 05m nonstop
Local times, typical schedule. Last flown 2026-05-31.
86%
chance on time
- On time (history)
- 87%
- Cancelled
- 1.3%
- Avg arrival delay
- 10 min
- Arrived on time 87% of the time (155 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 94% on time; After 9 PM: 59%).
- Departs outside LAS's trouble window (10 AM to 4 PM, when 51% of its 104 ground stops and delay programs started).
Moderate track record · 155 flights
Find Frontier 1283 fares Opens this date on Aviasales#3 · Southwest 2764
10:30 AM → 11:35 AM1h 05m nonstop
Local times, typical schedule. Last flown 2026-05-27.
84%
chance on time
- On time (history)
- 100%
- Cancelled
- 0.0%
- Avg arrival delay
- 0 min
- Arrived on time 100% of the time (16 flights, Jun 2025 to May 2026).
- Departs inside LAS's trouble window: 51% of its 104 ground stops and delay programs started between 10 AM and 4 PM.
- Short track record (16 flights), so its score leans on the airline's record at this hour.
Limited track record · 16 flights
Find Southwest 2764 fares Opens this date on Aviasales#4 · Southwest 384
9:20 AM → 10:25 AM1h 05m nonstop
Local times, typical schedule. Last flown 2026-04-06.
83%
chance on time
- On time (history)
- 87%
- Cancelled
- 0.0%
- Avg arrival delay
- 11 min
- Arrived on time 87% of the time (23 flights, Jun 2025 to May 2026).
- Departs outside LAS's trouble window (10 AM to 4 PM, when 51% of its 104 ground stops and delay programs started).
- Short track record (23 flights), so its score leans on the airline's record at this hour.
Limited track record · 23 flights
Find Southwest 384 fares Opens this date on Aviasales#5 · Frontier 1357
1:59 PM → 3:09 PM1h 10m nonstop
Local times, typical schedule. Last flown 2026-05-31.
83%
chance on time
- On time (history)
- 83%
- Cancelled
- 0.0%
- Avg arrival delay
- 15 min
- Arrived on time 83% of the time (230 flights, Jun 2025 to May 2026).
- Never cancelled in 230 scheduled flights.
- Departs inside LAS's trouble window: 51% of its 104 ground stops and delay programs started between 10 AM and 4 PM.
Strong track record · 230 flights
Find Frontier 1357 fares Opens this date on Aviasales#6 · Southwest 3054
10:15 AM → 11:20 AM1h 05m nonstop
Local times, typical schedule. Last flown 2026-05-29.
78%
chance on time
- On time (history)
- 81%
- Cancelled
- 0.0%
- Avg arrival delay
- 8 min
- Arrived on time 81% of the time (69 flights, Jun 2025 to May 2026).
- Never cancelled in 69 scheduled flights.
- Departs inside LAS's trouble window: 51% of its 104 ground stops and delay programs started between 10 AM and 4 PM.
Moderate track record · 69 flights
Find Southwest 3054 fares Opens this date on Aviasales#7 · Southwest 3624
10:40 AM → 11:45 AM1h 05m nonstop
Local times, typical schedule. Last flown 2026-05-31.
77%
chance on time
- On time (history)
- 75%
- Cancelled
- 0.0%
- Avg arrival delay
- 6 min
- Arrived on time 75% of the time (8 flights, Jun 2025 to May 2026).
- Departs inside LAS's trouble window: 51% of its 104 ground stops and delay programs started between 10 AM and 4 PM.
- Short track record (8 flights), so its score leans on the airline's record at this hour.
Limited track record · 8 flights
Find Southwest 3624 fares Opens this date on Aviasales#8 · Frontier 2231
6:22 PM → 7:32 PM1h 08m nonstop
Local times, typical schedule. Last flown 2026-05-18.
76%
chance on time
- On time (history)
- 77%
- Cancelled
- 1.7%
- Avg arrival delay
- 18 min
- Arrived on time 77% of the time (285 flights, Jun 2025 to May 2026).
- Departs outside LAS's trouble window (10 AM to 4 PM, when 51% of its 104 ground stops and delay programs started).
- 65% of its delay minutes came from the plane arriving late from an earlier flight.
Strong track record · 285 flights
Find Frontier 2231 fares Opens this date on Aviasales#9 · Southwest 2045
3:20 PM → 4:30 PM1h 10m nonstop
Local times, typical schedule. Last flown 2026-04-05.
76%
chance on time
- On time (history)
- 92%
- Cancelled
- 0.0%
- Avg arrival delay
- 3 min
- Arrived on time 92% of the time (13 flights, Jun 2025 to May 2026).
- Departs inside LAS's trouble window: 51% of its 104 ground stops and delay programs started between 10 AM and 4 PM.
- Short track record (13 flights), so its score leans on the airline's record at this hour.
Limited track record · 13 flights
Find Southwest 2045 fares Opens this date on Aviasales#10 · Southwest 3661
1:50 PM → 2:55 PM1h 05m nonstop
Local times, typical schedule. Last flown 2026-05-30.
76%
chance on time
- On time (history)
- 79%
- Cancelled
- 0.0%
- Avg arrival delay
- 7 min
- Arrived on time 79% of the time (24 flights, Jun 2025 to May 2026).
- Departs inside LAS's trouble window: 51% of its 104 ground stops and delay programs started between 10 AM and 4 PM.
- Short track record (24 flights), so its score leans on the airline's record at this hour.
Limited track record · 24 flights
Find Southwest 3661 fares Opens this date on Aviasales
Airlines on this route
Season-adjusted chance of operating and arriving on time.
- Frontier Airlines80%
720 flights · 81% on time as flown · 0.9% cancel
- Southwest Airlines74%
1,764 flights · 74% on time as flown · 0.7% cancel
On time by departure time
All airlines, scheduled local departure, Jun 2025 to May 2026.
- Before 9 AM94%
433 flights · avg delay 3 min
- 9 AM to noon84%
422 flights · avg delay 12 min
- Noon to 3 PM79%
409 flights · avg delay 13 min
- 3 to 6 PM70%
367 flights · avg delay 18 min
- 6 to 9 PM69%
568 flights · avg delay 20 min
- After 9 PM59%
285 flights · avg delay 23 min
Best day: Saturday (85%). Worst: Sunday (73%).
Smarter routing
Nearby airports that run more on time
LAS → SNA 82% chance on time
Harry Reid International Airport to John Wayne Orange County International Airport · 4,387 flights a year · 30 mi from your airports · yours: 76%
LAS → BUR 79% chance on time
Harry Reid International Airport to Hollywood Burbank/Bob Hope Airport · 4,278 flights a year · 44 mi from your airports · yours: 76%
LAS → LAX 78% chance on time
Harry Reid International Airport to Los Angeles International Airport · 8,424 flights a year · 47 mi from your airports · yours: 76%
LAS → LGB 78% chance on time
Harry Reid International Airport to Long Beach International Airport · 2,188 flights a year · 36 mi from your airports · yours: 76%
On time by month
All airlines, Jun 2023 to May 2026. Several years per month, so one stormy season doesn't define a month. Travel-month estimates use this seasonal pattern.
What delays this route
- Late-arriving aircraft63%
- Airline (crew, maintenance, boarding)29%
- Air traffic control and airport volume7%
- Severe weather2%
Share of delay minutes by the cause airlines report to the US DOT.
Historical odds, not a guarantee. Built from the US DOT Bureau of Transportation Statistics on-time reports (Jun 2025 to May 2026), FAA ground stop and delay program advisories, and 20 years of airport weather observations. Covers US airlines that report to the DOT; schedules are flights operated recently, so confirm times when you book. ATIS Alerts is not affiliated with any airline. Fares are what Aviasales travelers saw in recent searches (USD, one way, 1 adult), not live quotes; the partner site shows the current price. Fare links go to our travel partner and may earn us a commission at no cost to you. Affiliate disclosure
LAS to ONT questions
- What time of day is best to fly LAS to ONT?
- Before 9 AM: 94% of flights arrived on time, against 59% for departures after 9 PM. Later flights inherit delays from earlier ones, so the first departures of the day usually run best.
- Which airline is most on time from LAS to ONT?
- Frontier, with a season-adjusted 80% chance of operating and arriving on time over 720 flights. The adjustment compares each airline with what the route did in the months it flew, so a carrier that skipped a stormy month gets no free credit.
- What is the worst month for delays on LAS to ONT?
- June (70% on time); the best was January (85%), averaged over Jun 2023 to May 2026.
- Is this a prediction for my flight?
- No. These are historical odds from the US DOT on-time reports, FAA advisories and airport weather records. Check your flight status and the FAA delay board on the day you fly.
More routes from LAS
- ONT to LAS (return)
- LAS to LAX 79%
- LAS to DEN 77%
- LAS to SAN 68%
- LAS to PHX 78%
- LAS to SFO 66%
- LAS to SEA 82%
- LAS to ORD 77%
- LAS to DFW 81%
- LAS to ATL 84%
- LAS to SNA 82%
- LAS to SMF 79%
- LAS to BUR 80%
Live status: FAA delays and ground stops