Flight DL637
Delta Air Lines flight DL637
Looking for DL637 in the air…
Seattle (SEA) to Chicago (ORD)
Historically, this flight arrives 15+ minutes late 31% of the time, and when it is late the delay averages 54 minutes. It was cancelled 1.4% of the time.
- On-time arrivals
- 69.2%
- Less than 15 minutes late
- Cancelled
- 1.4%
- Of scheduled flights
- Average delay when late
- 54 min
- Flights arriving 15+ minutes late
- Flights tracked
- 138
- Scheduled flights in the period
What caused the delays
- Air traffic control & airport 67%
- Airline (crew, maintenance, cleaning) 24%
- Late-arriving aircraft 10%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
PBI → BOS
Historically, this flight arrives 15+ minutes late 45% of the time, and when it is late the delay averages 99 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 55.0%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 99 min
- Flights arriving 15+ minutes late
- Flights tracked
- 109
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 57%
- Airline (crew, maintenance, cleaning) 26%
- Air traffic control & airport 14%
- Extreme weather 2%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Chicago (ORD) to Seattle (SEA)
Historically, this flight arrives 15+ minutes late 39% of the time, and when it is late the delay averages 52 minutes. It was cancelled 2.0% of the time.
- On-time arrivals
- 61.2%
- Less than 15 minutes late
- Cancelled
- 2.0%
- Of scheduled flights
- Average delay when late
- 52 min
- Flights arriving 15+ minutes late
- Flights tracked
- 100
- Scheduled flights in the period
What caused the delays
- Airline (crew, maintenance, cleaning) 36%
- Air traffic control & airport 33%
- Late-arriving aircraft 29%
- Extreme weather 3%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Atlanta (ATL) to Chattanooga (CHA)
Historically, this flight arrives 15+ minutes late 18% of the time, and when it is late the delay averages 56 minutes. It was cancelled 2.9% of the time.
- On-time arrivals
- 81.8%
- Less than 15 minutes late
- Cancelled
- 2.9%
- Of scheduled flights
- Average delay when late
- 56 min
- Flights arriving 15+ minutes late
- Flights tracked
- 34
- Scheduled flights in the period
What caused the delays
- Airline (crew, maintenance, cleaning) 62%
- Late-arriving aircraft 38%
- Air traffic control & airport 0%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Chattanooga (CHA) to Atlanta (ATL)
Historically, this flight arrives 15+ minutes late 18% of the time, and when it is late the delay averages 110 minutes. It was cancelled 2.9% of the time.
- On-time arrivals
- 81.8%
- Less than 15 minutes late
- Cancelled
- 2.9%
- Of scheduled flights
- Average delay when late
- 110 min
- Flights arriving 15+ minutes late
- Flights tracked
- 34
- Scheduled flights in the period
What caused the delays
- Airline (crew, maintenance, cleaning) 59%
- Late-arriving aircraft 40%
- Air traffic control & airport 1%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Spokane (GEG) to Seattle (SEA)
Historically, this flight arrives 15+ minutes late 4% of the time, and when it is late the delay averages 52 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 95.7%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 52 min
- Flights arriving 15+ minutes late
- Flights tracked
- 23
- Scheduled flights in the period
What caused the delays
- Air traffic control & airport 55%
- Airline (crew, maintenance, cleaning) 45%
- Late-arriving aircraft 0%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
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Show as table
| Month | On time | Flights |
|---|---|---|
| September 2025 | 56.7% | 30 |
| October 2025 | 54.8% | 31 |
| November 2025 | 48.3% | 29 |
| December 2025 | 63.2% | 19 |
| January 2026 | 92.3% | 13 |
| February 2026 | 100.0% | 10 |
| March 2026 | 81.0% | 44 |
| April 2026 | 69.6% | 56 |
| May 2026 | 64.4% | 60 |
| June 2026 | 81.1% | 57 |
| July 2026 | 56.4% | 56 |
| August 2026 | 65.6% | 33 |
Source: U.S. DOT Bureau of Transportation Statistics on-time data, September 2025 – August 2026. Covers flights operated by reporting U.S. carriers. About our data