Route profile
ONT→ATL
Flight reliability, delays and best times to fly from Ontario to Atlanta, 1,900 miles.
Right now
Aviation weather is not currently a factor.
Aviation weather is not currently a factor.
Route reliability
July 2023 – July 2026
Better than 94% of comparable major US routes (4,598 compared)
Calculated from 2,919 flights. How this is calculated
ONT → ATL arrives on time 91.1% of the time; the return trip, ATL → ONT, arrives on time 76.3% of the time, a 14.8-point gap between the two directions of the same city pair.
ONT → ATL spends 22.7 minutes on the ground on a 1,900-mile trip: 14.5 minutes from pushback to wheels-up at ONT and 8.2 minutes from touchdown to gate at ATL.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
What stands out
Every day of the week performs about the same on this route, steadier than 100% of 4,467 comparable routes.
92.3% on time on the best day (Thursday) against 89.8% on the worst (Friday).
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Ranked against every other route with the same kind of figure and at least 4,467 in the comparison.
What sets this route apart
Where ONT to ATL differs most from similar routes by hour, weekday, month and airline, July 2023 – July 2026.
ONT to ATL is at its best against routes of similar length for flights scheduled at 10 PM: 93.3% arrive on time, 14.4 points ahead of the 78.9% those routes manage at that hour. Against all other routes the gap is 21.7 points.
ONT to ATL holds up on Sundays better than routes of similar length do: 91.0% on time to their 75.5%, a 15.5 points lead. Against all other routes the gap is 16.2 points.
June is kinder to ONT to ATL than to routes of similar length: 91.4% on time against 72.6%, 18.8 points better. Against all other routes the gap is 18.7 points.
Delta Air Lines does better on ONT to ATL than on its routes of similar length: 91.1% on time here, 81.5% there, 9.6 points apart. Against all other routes the gap is 9.6 points.
ONT to ATL against comparable routes
July 2023 – July 2026| Measure | This route | Compared with | Them | Gap | Flights behind it |
|---|---|---|---|---|---|
| Hour: 10 PM departures | 93.3% | routes of similar length | 78.9% | +14.4 pts | 683 here, 46,223 there |
| Weekday: Sunday | 91.0% | routes of similar length | 75.5% | +15.5 pts | 422 here, 169,909 there |
| Month: June | 91.4% | routes of similar length | 72.6% | +18.8 pts | 243 here, 104,009 there |
| Airline: Delta Air Lines | 91.1% | routes of similar length | 81.5% | +9.6 pts | 2,795 here, 299,194 there |
Each comparison pools the flights of other routes, with this route’s own left out. Similar length means within 15% of this route’s 1,900 miles, with at least 5 such routes. A bucket is set against the most comparable group that has enough flights: similar length, then the same origin (at least 3 routes), then all other routes. Hours, weekdays and months appear only where both sides have 120 completed flights, and airlines where both have 600. The gap must be at least 2 points and 2 standard errors, and only the largest gap each way is kept per measure. These are differences in the flights counted, not causes.
When it goes wrong
July 2023 – July 2026
13 min late
against a median of 12 min early
Percentiles over 2,919 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at ATL after arriving from ONT.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 21% | High risk |
| 45 min | 8.2% | Some risk |
| 60 min | 5.2% | Some risk |
| 90 min | 3.2% | Low risk |
| 120 min | 2.0% | Low risk |
This is one leg of a connection. Gate changes and the next flight's own schedule matter too. And a connection can fail before delay is even the question — this route cancels 1.37% of the time and diverts 0.65% of the time, which a late arrival never shows up in.
Chance of missing is the share of 2,860 arrivals on this route that landed later than the connection time less 30 minutes to reach the next gate.
The worst tenth of arrivals on this route land at least 13 minutes late (90th-percentile gate arrival delay), over 2,919 operations.
Any other layover length: connection checker.
Best time to fly
ONT → ATL flights departing 5–9 AM arrived on time 93.7% of the time, against 86.9% for 12–3 PM departures, a gap of 6.8 percentage points.
By departure window
By departure hour
- 12 AM to 5 AM: too few flights to score
- 6 AM: 90.9% on time from 203 flights
- 7 AM: 94.1% on time from 832 flights
- 8 AM to 10 AM: too few flights to score
- 11 AM: 89.0% on time from 413 flights
- 12 PM: 86.5% on time from 619 flights
- 1 PM to 9 PM: too few flights to score
- 10 PM: 93.3% on time from 697 flights
- 11 PM: too few flights to score
Why ONT → ATL runs late
July 2023 – July 2026
crew, maintenance, boarding and fueling, all within the carrier’s control
the inbound aircraft was late, so this flight started late
airspace and airport capacity, including weather-driven flow control
weather severe enough to stop this flight specifically
screening or terminal security incidents
Share of the delay minutes US DOT attributed to each cause for ONT → ATL. Only delays of 15 minutes or more are attributed.
Airlines on this route
Carriers with at least 200 flights, by the airline that operated each one.
| Carrier | Flights | On time | Cancelled | Median delay | Severe |
|---|---|---|---|---|---|
| Delta Air Lines | 2,852 | 91.1% | 1.33% | -12 min | 3.3% |
Other ways to fly Los Angeles to Atlanta
Airport pairs in the same two city markets, as the DOT defines them.
| Route | Flights | On time | Cancelled | Median delay | Score |
|---|---|---|---|---|---|
| LAX→ATL Los Angeles to Atlanta | 16,272 | 78.7% | 0.84% | -5 min | 68 |
| ONT→ATL this route Ontario to Atlanta | 2,919 | 91.1% | 1.37% | -12 min | 85 |
ONT → ATL is the most reliable pairing for this journey at 91.1% on time, against 78.7% for LAX → ATL.
Flying to ATL from the Los Angeles area? Compare ONT, LAX, SNA, BUR for ATL, with the same test for what counts as a real difference.
Flights on this route
Flight numbers with at least 600 operations here and still on the schedule.
| Flight | Scheduled | Operations | On time |
|---|---|---|---|
| DL761 Delta Air Lines | 7:05 AM | 784 | 92.3% |
Weekly and seasonal patterns
By day of week
Thursday is historically the most reliable day and Friday the least, a gap of 2.5 percentage points.
By month
- Jan: 88.7%
- Feb: 93.5%
- Mar: 90.1%
- Apr: 88.9%
- May: 87.3%
- Jun: 91.4%
- Jul: 88.1%
- Aug: 90.8%
- Sep: 96.6%
- Oct: 91.5%
- Nov: 93.5%
- Dec: 94.4%
May is historically the weakest month and September the strongest, a spread of 9.3 percentage points.
Reliability over time
July 2023 – July 2026
- July 2023: too few flights to score (118)
- August 2023: 85.5% from 121 flights
- September 2023: too few flights to score (82)
- October 2023: too few flights to score (78)
- November 2023: too few flights to score (72)
- December 2023: too few flights to score (80)
- January 2024: too few flights to score (63)
- February 2024: too few flights to score (58)
- March 2024: too few flights to score (62)
- April 2024: too few flights to score (72)
- May 2024: too few flights to score (79)
- June 2024: too few flights to score (87)
- July 2024: too few flights to score (82)
- August 2024: too few flights to score (85)
- September 2024: too few flights to score (80)
- October 2024: too few flights to score (84)
- November 2024: too few flights to score (77)
- December 2024: too few flights to score (88)
- January 2025: too few flights to score (66)
- February 2025: too few flights to score (56)
- March 2025: too few flights to score (62)
- April 2025: too few flights to score (77)
- May 2025: too few flights to score (81)
- June 2025: too few flights to score (84)
- July 2025: too few flights to score (88)
- August 2025: too few flights to score (82)
- September 2025: too few flights to score (77)
- October 2025: too few flights to score (85)
- November 2025: too few flights to score (84)
- December 2025: too few flights to score (88)
- January 2026: too few flights to score (65)
- February 2026: too few flights to score (56)
- March 2026: too few flights to score (62)
- April 2026: too few flights to score (77)
- May 2026: too few flights to score (93)
- June 2026: too few flights to score (80)
- July 2026: too few flights to score (88)
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 89.2% against 92.0% in the 12 months before — declining by 2.8 percentage points.
Data and methodology
Calculated by FlyerIntel from 2,919 ONT → ATL flight records from the US DOT Bureau of Transportation Statistics, covering July 2023 – July 2026. Late means 15 or more minutes past scheduled arrival; cancelled and diverted flights are left out of on-time rates.
Full methodology · Data sources · Report a problem
Related research: How Long a Layover Needs to Be · Two Airlines on One Route · Best Time of Day to Fly From Major US Airports
Analysis last recomputed