Flight UA323
United Airlines flight UA323
Looking for UA323 in the air…
Alerts at this flight's airports
Boston (BOS) to San Francisco (SFO)
Historically, this flight arrives 15+ minutes late 15% of the time, and when it is late the delay averages 39 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 85.1%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 39 min
- Flights arriving 15+ minutes late
- Flights tracked
- 47
- Scheduled flights in the period
What caused the delays
- Air traffic control & airport 88%
- Late-arriving aircraft 12%
- Airline (crew, maintenance, cleaning) 0%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Houston (IAH) to Cincinnati / Covington (CVG)
Historically, this flight arrives 15+ minutes late 17% of the time, and when it is late the delay averages 59 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 83.0%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 59 min
- Flights arriving 15+ minutes late
- Flights tracked
- 47
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 69%
- Air traffic control & airport 12%
- Airline (crew, maintenance, cleaning) 11%
- Extreme weather 8%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Columbus (CMH) to Chicago (ORD)
Historically, this flight arrives 15+ minutes late 34% of the time, and when it is late the delay averages 113 minutes. It was cancelled 5.4% of the time.
- On-time arrivals
- 65.7%
- Less than 15 minutes late
- Cancelled
- 5.4%
- Of scheduled flights
- Average delay when late
- 113 min
- Flights arriving 15+ minutes late
- Flights tracked
- 37
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 50%
- Air traffic control & airport 36%
- Airline (crew, maintenance, cleaning) 14%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Boise (BOI) to Chicago (ORD)
Historically, this flight arrives 15+ minutes late 29% of the time, and when it is late the delay averages 103 minutes. It was cancelled 2.8% of the time.
- On-time arrivals
- 71.4%
- Less than 15 minutes late
- Cancelled
- 2.8%
- Of scheduled flights
- Average delay when late
- 103 min
- Flights arriving 15+ minutes late
- Flights tracked
- 36
- Scheduled flights in the period
What caused the delays
- Air traffic control & airport 56%
- Late-arriving aircraft 36%
- Airline (crew, maintenance, cleaning) 7%
- Extreme weather 1%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Burlington (BTV) to Denver (DEN)
Historically, this flight arrives 15+ minutes late 41% of the time, and when it is late the delay averages 70 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 58.8%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 70 min
- Flights arriving 15+ minutes late
- Flights tracked
- 35
- Scheduled flights in the period
What caused the delays
- Airline (crew, maintenance, cleaning) 42%
- Late-arriving aircraft 30%
- Air traffic control & airport 26%
- Extreme weather 2%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Denver (DEN) to Charlotte (CLT)
Historically, this flight arrives 15+ minutes late 38% of the time, and when it is late the delay averages 49 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 62.5%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 49 min
- Flights arriving 15+ minutes late
- Flights tracked
- 24
- Scheduled flights in the period
What caused the delays
- Air traffic control & airport 54%
- Late-arriving aircraft 32%
- Airline (crew, maintenance, cleaning) 13%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Newark (EWR) to Las Vegas (LAS)
Historically, this flight arrives 15+ minutes late 12% of the time, and when it is late the delay averages 31 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 87.5%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 31 min
- Flights arriving 15+ minutes late
- Flights tracked
- 24
- 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).
Newark (EWR) to Cleveland (CLE)
Historically, this flight arrives 15+ minutes late 9% of the time, and when it is late the delay averages 90 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 90.9%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 90 min
- Flights arriving 15+ minutes late
- Flights tracked
- 22
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 71%
- Airline (crew, maintenance, cleaning) 29%
- Air traffic control & airport 0%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Buffalo (BUF) to Chicago (ORD)
Historically, this flight arrives 15+ minutes late 24% of the time, and when it is late the delay averages 99 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 76.2%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 99 min
- Flights arriving 15+ minutes late
- Flights tracked
- 21
- Scheduled flights in the period
What caused the delays
- Air traffic control & airport 90%
- Airline (crew, maintenance, cleaning) 10%
- Late-arriving aircraft 0%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Dayton (DAY) to Denver (DEN)
Only 19 flights on record, which is too few for reliable odds.
- On-time arrivals
- 94.7%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 34 min
- Flights arriving 15+ minutes late
- Flights tracked
- 19
- Scheduled flights in the period
What caused the delays
- Extreme weather 62%
- Air traffic control & airport 38%
- Airline (crew, maintenance, cleaning) 0%
- Late-arriving aircraft 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Cleveland (CLE) to Houston (IAH)
Only 18 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
- 46 min
- Flights arriving 15+ minutes late
- Flights tracked
- 18
- 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).
Denver (DEN) to Tampa (TPA)
Only 16 flights on record, which is too few for reliable odds.
- On-time arrivals
- 66.7%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 89 min
- Flights arriving 15+ minutes late
- Flights tracked
- 16
- Scheduled flights in the period
What caused the delays
- Airline (crew, maintenance, cleaning) 59%
- Late-arriving aircraft 30%
- Air traffic control & airport 11%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Chicago (ORD) to Columbus (CMH)
Only 6 flights on record, which is too few for reliable odds.
- On-time arrivals
- 66.7%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 35 min
- Flights arriving 15+ minutes late
- Flights tracked
- 6
- Scheduled flights in the period
What caused the delays
- Air traffic control & airport 67%
- Airline (crew, maintenance, cleaning) 21%
- Late-arriving aircraft 12%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Newark (EWR) to Tampa (TPA)
Only 3 flights 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
- —
- Flights arriving 15+ minutes late
- Flights tracked
- 3
- Scheduled flights in the period
Fayetteville/Springdale/Rogers (XNA) to Houston (IAH)
Only 2 flights 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
- —
- Flights arriving 15+ minutes late
- Flights tracked
- 2
- Scheduled flights in the period
Newark (EWR) to Minneapolis (MSP)
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
- —
- Flights arriving 15+ minutes late
- Flights tracked
- 1
- Scheduled flights in the period
Chicago (ORD) to Dulles (IAD)
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
- —
- 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 | 85.7% | 28 |
| October 2025 | 92.6% | 27 |
| November 2025 | 72.4% | 30 |
| December 2025 | 76.7% | 31 |
| January 2026 | 69.0% | 31 |
| February 2026 | 89.3% | 28 |
| March 2026 | 67.7% | 31 |
| April 2026 | 76.7% | 30 |
| May 2026 | 83.3% | 31 |
| June 2026 | 56.7% | 30 |
| July 2026 | 83.9% | 31 |
| August 2026 | 80.6% | 31 |
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