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Route on-time record

PDX to ONT: most on-time flights and the best time to fly

Portland (Portland International Airport) to Ontario (Ontario International Airport). 523 nonstop flights in Jun 2025 to May 2026, 83% arrived within 15 minutes and 0.4% were cancelled. The most reliable flight number was Alaska 1333 at 8:00 AM.

Flying on a specific date? We’ll adjust for the month, the weekday and the forecast.

PDX → ONT

Portland to Ontario: 523 nonstop flights a year

On time (12 months)

83%

Cancelled

0.4%

avg delay 10 min

Best time to leave

3 to 6 PM

87% on time vs 82% after 9 PM

Most reliable airline

Alaska

84% chance on time

Check PDX to ONT fares

Lowest nonstop fare seen in the next two months: $103 (Southwest 332 on 2026-10-20). 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. #1 · Alaska 1333

    8:00 AM → 10:21 AM2h 21m nonstop

    Local times, typical schedule. Last flown 2026-05-31.

    88%

    chance on time

    On time (history)
    94%
    Cancelled
    0.0%
    Avg arrival delay
    2 min
    • Arrived on time 94% of the time (18 flights, Jun 2025 to May 2026).
    • Short track record (18 flights), so its score leans on the airline's record at this hour.

    Limited track record · 18 flights

    Find Alaska 1333 fares Opens this date on Aviasales

  2. #2 · Alaska 565

    2:50 PM → 5:14 PM2h 24m nonstop

    Local times, typical schedule. Last flown 2026-03-16.

    87%

    chance on time

    On time (history)
    89%
    Cancelled
    0.0%
    Avg arrival delay
    11 min
    • Arrived on time 89% of the time (56 flights, Jun 2025 to May 2026).
    • Never cancelled in 56 scheduled flights.
    • Short track record (56 flights), so its score leans on the airline's record at this hour.

    Limited track record · 56 flights

    Find Alaska 565 fares Opens this date on Aviasales

  3. #3 · SkyWest 3427 · sold as United Express, Delta Connection, American Eagle or Alaska

    2:48 PM → 5:13 PM2h 25m nonstop

    Local times, typical schedule. Last flown 2026-05-11.

    86%

    chance on time

    On time (history)
    100%
    Cancelled
    0.0%
    Avg arrival delay
    1 min
    • Arrived on time 100% of the time (12 flights, Jun 2025 to May 2026).
    • Short track record (12 flights), so its score leans on the airline's record at this hour.

    Limited track record · 12 flights

    Find 2:48 PM flight fares Opens this date on Aviasales

  4. #4 · Alaska 97

    5:58 PM → 8:23 PM2h 25m nonstop

    Local times, typical schedule. Last flown 2026-05-11.

    83%

    chance on time

    On time (history)
    82%
    Cancelled
    0.0%
    Avg arrival delay
    10 min
    • Arrived on time 82% of the time (122 flights, Jun 2025 to May 2026).
    • Never cancelled in 122 scheduled flights.
    • Leaves in this route's most on-time window (3 to 6 PM: 87% on time; After 9 PM: 82%).

    Moderate track record · 122 flights

    Find Alaska 97 fares Opens this date on Aviasales

  5. #5 · Alaska 340

    9:30 PM → 11:52 PM2h 22m nonstop

    Local times, typical schedule. Last flown 2026-03-17.

    80%

    chance on time

    On time (history)
    78%
    Cancelled
    0.0%
    Avg arrival delay
    13 min
    • Arrived on time 78% of the time (65 flights, Jun 2025 to May 2026).
    • Never cancelled in 65 scheduled flights.
    • Leaves in this route's least on-time window (After 9 PM: 82% on time; 3 to 6 PM: 87%).

    Moderate track record · 65 flights

    Find Alaska 340 fares Opens this date on Aviasales

Airlines on this route

Season-adjusted chance of operating and arriving on time.

  • Alaska Airlines84%

    352 flights · 84% on time as flown · 0.5% cancel

  • SkyWest Airlines (sold as United Express, Delta Connection, American Eagle or Alaska)82%

    62 flights · 82% on time as flown · 0.3% cancel

  • Frontier Airlines82%

    109 flights · 82% on time as flown · 0.2% cancel

On time by departure time

All airlines, scheduled local departure, Jun 2025 to May 2026.

  • 9 AM to noon83%

    46 flights · avg delay 9 min

  • Noon to 3 PM82%

    183 flights · avg delay 11 min

  • 3 to 6 PM87%

    102 flights · avg delay 10 min

  • 6 to 9 PM83%

    30 flights · avg delay 15 min

  • After 9 PM82%

    142 flights · avg delay 9 min

Best day: Saturday (88%). Worst: Sunday (83%).

Smarter routing

Nearby airports that run more on time

  • PDX → SNA 89% chance on time

    Portland International Airport to John Wayne Orange County International Airport · 1,543 flights a year · 30 mi from your airports · yours: 83%

    Rank flightsFares

  • PDX → LAX 86% chance on time

    Portland International Airport to Los Angeles International Airport · 4,447 flights a year · 47 mi from your airports · yours: 83%

    Rank flightsFares

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.

J
83
F
86
M
92
A
88
M
90
J
83
J
85
A
76
S
84
O
90
N
85
D
79

What delays this route

  • Airline (crew, maintenance, boarding)51%
  • Late-arriving aircraft39%
  • Air traffic control and airport volume10%

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

PDX to ONT questions

What time of day is best to fly PDX to ONT?
3 to 6 PM: 87% of flights arrived on time, against 82% for departures after 9 PM.
Which airline is most on time from PDX to ONT?
Alaska, with a season-adjusted 84% chance of operating and arriving on time over 352 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 PDX to ONT?
August (76% on time); the best was March (92%), 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 PDX

Live status: FAA delays and ground stops