Flight UA399
United Airlines flight UA399
Looking for UA399 in the airâŚ
Alerts at this flight's airports
-
Advisory Coastal Flood Statement FLL
COASTAL FLOOD STATEMENT NOW IN EFFECT THROUGH THURSDAY EVENING
Weather
Chicago (ORD) to Boston (BOS)
Historically, this flight arrives 15+ minutes late 42% of the time, and when it is late the delay averages 72 minutes. It was cancelled 2.5% of the time.
- On-time arrivals
- 58.2%
- Less than 15 minutes late
- Cancelled
- 2.5%
- Of scheduled flights
- Average delay when late
- 72 min
- Flights arriving 15+ minutes late
- Flights tracked
- 162
- Scheduled flights in the period
What caused the delays
- Air traffic control & airport 56%
- Late-arriving aircraft 34%
- Airline (crew, maintenance, cleaning) 6%
- Extreme weather 4%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Newark (EWR) to New Orleans (MSY)
Historically, this flight arrives 15+ minutes late 12% of the time, and when it is late the delay averages 39 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
- 39 min
- Flights arriving 15+ minutes late
- Flights tracked
- 32
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 60%
- Airline (crew, maintenance, cleaning) 29%
- Air traffic control & airport 11%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Newark (EWR) to Fort Lauderdale (FLL)
Historically, this flight arrives 15+ minutes late 43% of the time, and when it is late the delay averages 76 minutes. It was cancelled 4.2% of the time.
- On-time arrivals
- 56.5%
- Less than 15 minutes late
- Cancelled
- 4.2%
- Of scheduled flights
- Average delay when late
- 76 min
- Flights arriving 15+ minutes late
- Flights tracked
- 24
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 55%
- Airline (crew, maintenance, cleaning) 24%
- Air traffic control & airport 21%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Dallas-Fort Worth (DFW) to Houston (IAH)
Historically, this flight arrives 15+ minutes late 29% of the time, and when it is late the delay averages 104 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 71.4%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 104 min
- Flights arriving 15+ minutes late
- Flights tracked
- 21
- Scheduled flights in the period
What caused the delays
- Air traffic control & airport 73%
- Extreme weather 23%
- Late-arriving aircraft 3%
- Airline (crew, maintenance, cleaning) 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Houston (IAH) to San Francisco (SFO)
Historically, this flight arrives 15+ minutes late 43% of the time, and when it is late the delay averages 50 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
- 50 min
- Flights arriving 15+ minutes late
- Flights tracked
- 21
- Scheduled flights in the period
What caused the delays
- Air traffic control & airport 56%
- Late-arriving aircraft 29%
- Airline (crew, maintenance, cleaning) 15%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Seattle (SEA) to Denver (DEN)
Historically, this flight arrives 15+ minutes late 14% of the time, and when it is late the delay averages 86 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 85.7%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 86 min
- Flights arriving 15+ minutes late
- Flights tracked
- 21
- Scheduled flights in the period
What caused the delays
- Air traffic control & airport 83%
- Late-arriving aircraft 17%
- Airline (crew, maintenance, cleaning) 0%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Chicago (ORD) to Dallas-Fort Worth (DFW)
Historically, this flight arrives 15+ minutes late 21% of the time, and when it is late the delay averages 42 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 78.9%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 42 min
- Flights arriving 15+ minutes late
- Flights tracked
- 20
- Scheduled flights in the period
What caused the delays
- Airline (crew, maintenance, cleaning) 37%
- Air traffic control & airport 32%
- Extreme weather 21%
- Late-arriving aircraft 10%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Houston (IAH) to Charlotte (CLT)
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
- â
- Flights arriving 15+ minutes late
- Flights tracked
- 2
- Scheduled flights in the period
Boston (BOS) to Newark (EWR)
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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Headlines found by Google News; stories open on the publisher's site.
Show as table
| Month | On time | Flights |
|---|---|---|
| September 2025 | 32.3% | 31 |
| October 2025 | 51.6% | 31 |
| November 2025 | 71.4% | 30 |
| December 2025 | 61.3% | 31 |
| January 2026 | 75.9% | 31 |
| February 2026 | 78.6% | 28 |
| March 2026 | 66.7% | 31 |
| April 2026 | 80.6% | 31 |
| May 2026 | 71.2% | 60 |
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