Flight Reliability
DL 634 · Delta Air Lines
Detroit → Los Angeles (DTW–LAX)93% of its flights flew this route. The rest (ONT–SLC, SLC–ONT) are included in these numbers.
- 84%
- Arrive within 15 minutes
- 1 min early
- Average arrival delay
- 1.1%
- Cancelled
- 7 min early
- Median arrival delay
Based on 375 historical flights. Data through May 2026.
What the data says
The 12–3 PM departure wins.
DL 634 departing between 12–3 PM arrived on time 84% of the time, versus 75% between 3–6 PM.
Sunday scaries are real for this one.
DL 634 arrived on time 92% of the time on Thursdays and just 72% on Sundays. That gap is worth planning around.
A bit ahead of the DTW–LAX route.
DL 634 arrived on time 84% of the time, versus 79% across the DTW–LAX route.
Ticking up lately.
DL 634 arrived on time 85% of the time over the last three months in the data, compared with 80% in the three months before that.
The breakdown
- Mon87%(54 flights)
- Tue87%(53 flights)
- Wed89%(52 flights)
- Thu92%(52 flights)
- Fri79%(53 flights)
- Sat83%(53 flights)
- Sun72%(54 flights)
- 9 AM–12 PM—(4 flights)
- 12–3 PM84%(347 flights)
- 3–6 PM75%(20 flights)
Jun 87% → May 87% on time
| Month | On-time percentage | Flights |
|---|---|---|
| June 2025 | 87% | 30 |
| July 2025 | 84% | 31 |
| August 2025 | 93% | 30 |
| September 2025 | 80% | 30 |
| October 2025 | 84% | 31 |
| November 2025 | 90% | 30 |
| December 2025 | 75% | 40 |
| January 2026 | 80% | 30 |
| February 2026 | 86% | 28 |
| March 2026 | 87% | 30 |
| April 2026 | 80% | 30 |
| May 2026 | 87% | 31 |
- Departures on time
- 85%
- Diverted
- 0%
- Flights flown
- 371
- Months covered
- 12
Same route, other flights
Keep nerding
Based on 375 historical flights, because apparently we checked. Historical flight data: U.S. Bureau of Transportation Statistics, June 2025 – May 2026. Data through May 2026. How we calculate this.