Flight UA638
United Airlines flight UA638
Looking for UA638 in the airâŚ
Alerts at this flight's airports
San Francisco (SFO) to Honolulu, Oahu (HNL)
Historically, this flight arrives 15+ minutes late 13% of the time, and when it is late the delay averages 72 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 87.0%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 72 min
- Flights arriving 15+ minutes late
- Flights tracked
- 262
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 68%
- Airline (crew, maintenance, cleaning) 28%
- Air traffic control & airport 4%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Philadelphia (PHL) to Denver (DEN)
Historically, this flight arrives 15+ minutes late 17% of the time, and when it is late the delay averages 109 minutes. It was cancelled 2.7% of the time.
- On-time arrivals
- 83.3%
- Less than 15 minutes late
- Cancelled
- 2.7%
- Of scheduled flights
- Average delay when late
- 109 min
- Flights arriving 15+ minutes late
- Flights tracked
- 37
- Scheduled flights in the period
What caused the delays
- Airline (crew, maintenance, cleaning) 58%
- Air traffic control & airport 25%
- Late-arriving aircraft 17%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Albuquerque (ABQ) to San Francisco (SFO)
Historically, this flight arrives 15+ minutes late 20% of the time, and when it is late the delay averages 81 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 80.0%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 81 min
- Flights arriving 15+ minutes late
- Flights tracked
- 30
- Scheduled flights in the period
What caused the delays
- Air traffic control & airport 87%
- Late-arriving aircraft 10%
- Airline (crew, maintenance, cleaning) 3%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Denver (DEN) to Los Angeles (LAX)
Historically, this flight arrives 15+ minutes late 19% of the time, and when it is late the delay averages 62 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 81.0%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 62 min
- Flights arriving 15+ minutes late
- Flights tracked
- 21
- Scheduled flights in the period
What caused the delays
- Airline (crew, maintenance, cleaning) 49%
- Late-arriving aircraft 41%
- Air traffic control & airport 10%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Denver (DEN) to Tampa (TPA)
Historically, this flight arrives 15+ minutes late 43% of the time, and when it is late the delay averages 61 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 57.1%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 61 min
- Flights arriving 15+ minutes late
- Flights tracked
- 21
- Scheduled flights in the period
What caused the delays
- Air traffic control & airport 40%
- Late-arriving aircraft 35%
- Airline (crew, maintenance, cleaning) 24%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Denver (DEN) to Fairbanks (FAI)
Only 18 flights on record, which is too few for reliable odds.
- On-time arrivals
- 88.9%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 101 min
- Flights arriving 15+ minutes late
- Flights tracked
- 18
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 83%
- Air traffic control & airport 11%
- Airline (crew, maintenance, cleaning) 6%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
New Orleans (MSY) to San Francisco (SFO)
Only 15 flights on record, which is too few for reliable odds.
- On-time arrivals
- 53.3%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 130 min
- Flights arriving 15+ minutes late
- Flights tracked
- 15
- Scheduled flights in the period
What caused the delays
- Air traffic control & airport 94%
- Airline (crew, maintenance, cleaning) 6%
- Late-arriving aircraft 0%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Denver (DEN) to Boise (BOI)
Only 1 flight on record, which is too few for reliable odds.
- On-time arrivals
- 100.0%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- â
- Flights arriving 15+ minutes late
- Flights tracked
- 1
- Scheduled flights in the period
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Show as table
| Month | On time | Flights |
|---|---|---|
| September 2025 | 88.0% | 25 |
| October 2025 | 83.3% | 36 |
| November 2025 | 88.9% | 54 |
| December 2025 | 83.7% | 43 |
| January 2026 | 70.6% | 35 |
| February 2026 | 89.3% | 28 |
| March 2026 | 90.3% | 31 |
| April 2026 | 96.7% | 30 |
| May 2026 | 83.9% | 31 |
| June 2026 | 76.7% | 30 |
| July 2026 | 80.6% | 31 |
| August 2026 | 64.5% | 31 |
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