Flight UA644
United Airlines flight UA644
Looking for UA644 in the airâŚ
Alerts at this flight's airports
Denver (DEN) to Portland (PDX)
Historically, this flight arrives 15+ minutes late 16% of the time, and when it is late the delay averages 54 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 84.3%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 54 min
- Flights arriving 15+ minutes late
- Flights tracked
- 312
- Scheduled flights in the period
What caused the delays
- Airline (crew, maintenance, cleaning) 51%
- Air traffic control & airport 25%
- Late-arriving aircraft 22%
- Extreme weather 2%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Dallas-Fort Worth (DFW) to Denver (DEN)
Historically, this flight arrives 15+ minutes late 15% of the time, and when it is late the delay averages 57 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 85.5%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 57 min
- Flights arriving 15+ minutes late
- Flights tracked
- 124
- Scheduled flights in the period
What caused the delays
- Airline (crew, maintenance, cleaning) 79%
- Air traffic control & airport 14%
- Extreme weather 5%
- Late-arriving aircraft 3%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Nashville (BNA) to Houston (IAH)
Historically, this flight arrives 15+ minutes late 15% of the time, and when it is late the delay averages 32 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 84.6%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 32 min
- Flights arriving 15+ minutes late
- Flights tracked
- 52
- Scheduled flights in the period
What caused the delays
- Air traffic control & airport 56%
- Airline (crew, maintenance, cleaning) 44%
- Late-arriving aircraft 0%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Portland (PDX) to San Francisco (SFO)
Historically, this flight arrives 15+ minutes late 22% of the time, and when it is late the delay averages 154 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 77.8%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 154 min
- Flights arriving 15+ minutes late
- Flights tracked
- 27
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 95%
- Air traffic control & airport 5%
- Airline (crew, maintenance, cleaning) 0%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
San Francisco (SFO) to Eugene (EUG)
Historically, this flight arrives 15+ minutes late 31% of the time, and when it is late the delay averages 97 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 69.2%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 97 min
- Flights arriving 15+ minutes late
- Flights tracked
- 26
- Scheduled flights in the period
What caused the delays
- Airline (crew, maintenance, cleaning) 69%
- Late-arriving aircraft 28%
- Air traffic control & airport 2%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Dulles (IAD) to Denver (DEN)
Historically, this flight arrives 15+ minutes late 10% of the time, and when it is late the delay averages 42 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 90.0%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 42 min
- Flights arriving 15+ minutes late
- Flights tracked
- 21
- Scheduled flights in the period
What caused the delays
- Air traffic control & airport 51%
- Airline (crew, maintenance, cleaning) 49%
- Late-arriving aircraft 0%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Syracuse (SYR) to Denver (DEN)
Historically, this flight arrives 15+ minutes late 10% of the time, and when it is late the delay averages 54 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 90.5%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 54 min
- Flights arriving 15+ minutes late
- Flights tracked
- 21
- Scheduled flights in the period
What caused the delays
- Airline (crew, maintenance, cleaning) 60%
- Air traffic control & airport 40%
- Late-arriving aircraft 0%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Miami (MIA) to Denver (DEN)
Only 19 flights on record, which is too few for reliable odds.
- On-time arrivals
- 94.4%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 43 min
- Flights arriving 15+ minutes late
- Flights tracked
- 19
- Scheduled flights in the period
What caused the delays
- Airline (crew, maintenance, cleaning) 100%
- Late-arriving aircraft 0%
- Air traffic control & airport 0%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Philadelphia (PHL) to Denver (DEN)
Only 11 flights on record, which is too few for reliable odds.
- On-time arrivals
- 90.9%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 34 min
- Flights arriving 15+ minutes late
- Flights tracked
- 11
- Scheduled flights in the period
What caused the delays
- Airline (crew, maintenance, cleaning) 58%
- Air traffic control & airport 42%
- Late-arriving aircraft 0%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Bozeman (BZN) to Denver (DEN)
Only 1 flight on record, which is too few for reliable odds.
- On-time arrivals
- 0.0%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 33 min
- Flights arriving 15+ minutes late
- Flights tracked
- 1
- Scheduled flights in the period
What caused the delays
- Air traffic control & airport 100%
- Airline (crew, maintenance, cleaning) 0%
- 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 | 79.5% | 83 |
| October 2025 | 87.1% | 31 |
| November 2025 | 83.3% | 30 |
| December 2025 | 86.4% | 45 |
| January 2026 | 80.6% | 36 |
| February 2026 | 84.4% | 45 |
| March 2026 | 89.5% | 38 |
| April 2026 | 95.0% | 60 |
| May 2026 | 86.9% | 62 |
| June 2026 | 78.3% | 60 |
| July 2026 | 87.1% | 62 |
| August 2026 | 77.4% | 62 |
Source: U.S. DOT Bureau of Transportation Statistics on-time data, September 2025 â August 2026. Covers flights operated by reporting U.S. carriers. About our data