UAL8121

UNITED AIRLINES INC · SFO → DEN

UAL8121 is operated by UNITED AIRLINES INC between San Francisco International Airport (KSFO) and Denver International Airport (KDEN). The flight is most often flown by a AIRBUS Airbus A321 Neo. Typical block time is 2h 23m. SkyMeter has observed 34 legs of this flight number via ADS-B.

✈
FLIGHTS
34
last 90 days
⏱
AVG DURATION
2h 23m
tracked time
📅
SERVICE PERIOD
05/29/2025 → 07/14/2026
first → last seen
🗺
ROUTES / TYPES
29 / 10
city pairs · airframes
⚠
INCIDENT RATE
0.0%
0 flagged

Routes flown

By count · last 90 days

10
KSFO → KDEN
3
avg 2h 41m · San Francisco → Denver
KIAH → KMSY
2
avg 55m · George Bush Intercontinental Houston → Louis Armstrong New Orleans
KSFO → KLAX
2
avg 58m · San Francisco → Los Angeles
KDEN → KCID
1
avg 1h 29m · Denver → The Eastern Iowa
KORD → KIAD
1
avg 1h 52m · Chicago O'Hare → Washington Dulles
KIAH → KATL
1
avg 1h 42m · George Bush Intercontinental Houston → Hartsfield Jackson Atlanta
KFLL → KSFO
1
avg 5h 45m · Fort Lauderdale Hollywood → San Francisco
KBNA → KORD
1
avg 1h 25m · Nashville → Chicago O'Hare
US-0263 → KBOS
1
avg 2h 8m · Ravenswood → General Edward Lawrence Logan
KHAF → KMFR
1
avg 1h 31m · Half Moon Bay → Rogue Valley International Medford

Aircraft types

Equipment used on this number

10
A21N AIRBUS Airbus A321 Neo
10
B39M BOEING Boeing 737 MAX 9
9
A320 AIRBUS Airbus A320
4
B739 BOEING Boeing 737-900
4
B38M BOEING Boeing 737 MAX 8
3
B738 BOEING Boeing 737-800
3
B752 BOEING Boeing 757-200
2
A319 AIRBUS Airbus A319
2
B737 BOEING Boeing 737-700
2
B753 BOEING Boeing 757-300
1

Safety profile

Flagged flights · last 90 days

Go-arounds
0
Unstable approach
0
Rejected TO
0
Stall warnings
0
Overspeeds
0
Runway excursion
0
Counts represent flights with at least one occurrence of each flag, not the total event count. See /incidents for individual events.

Recent flights

Newest 30 operations of UAL8121

30
N17229BOEING Boeing 737-800
→
07/14/2026
1h 42m
No alerts
Replay Analysis
N37527BOEING Boeing 737 MAX 9
→
07/12/2026
5h 28m
No alerts
Replay Analysis
N66837BOEING Boeing 737-900
→
07/11/2026
2h 16m
No alerts
Replay Analysis
N17245BOEING Boeing 737-800
→
07/10/2026
2h 10m
No alerts
Replay Analysis
N807UAAIRBUS Airbus A319
→
07/10/2026
1h 59m
No alerts
Replay Analysis
N14524AIRBUS Airbus A321 Neo
→
07/06/2026
3h 40m
No alerts
Replay Analysis
N65832BOEING Boeing 737-900
→
07/05/2026
1h 31m
No alerts
Replay Analysis
N14502AIRBUS Airbus A321 Neo
→
07/04/2026
1h 45m
No alerts
Replay Analysis
N14502AIRBUS Airbus A321 Neo
→
07/03/2026
21m
No alerts
Replay Analysis
N14502AIRBUS Airbus A321 Neo
→
07/03/2026
2h 7m
No alerts
Replay Analysis
N57862BOEING Boeing 757-300
→
06/25/2026
4h 20m
No alerts
Replay Analysis
N441UAAIRBUS Airbus A320
→
06/23/2026
2h 26m
No alerts
Replay Analysis
N77580BOEING Boeing 737 MAX 9
→
06/22/2026
1h 31m
No alerts
Replay Analysis
N459UAAIRBUS Airbus A320
→
06/21/2026
36m
No alerts
Replay Analysis
N27404BOEING Boeing 737 MAX 9
→
06/20/2026
5h 45m
No alerts
Replay Analysis
N29717BOEING Boeing 737-700
→
06/20/2026
1h 22m
No alerts
Replay Analysis
N478UAAIRBUS Airbus A320
→
06/18/2026
2h 3m
No alerts
Replay Analysis
N831UAAIRBUS Airbus A319
→
06/18/2026
59m
No alerts
Replay Analysis
N24729BOEING Boeing 737-700
→
06/17/2026
2h 41m
No alerts
Replay Analysis
N57299BOEING Boeing 737 MAX 8
→
06/14/2026
4h 35m
No alerts
Replay Analysis
N69826BOEING Boeing 737-900
→
06/11/2026
1h 51m
No alerts
Replay Analysis
N37440BOEING Boeing 737 MAX 9
→
06/11/2026
16m
No alerts
Replay Analysis
N37440BOEING Boeing 737 MAX 9
→
06/10/2026
36m
No alerts
Replay Analysis
N37440BOEING Boeing 737 MAX 9
→
06/10/2026
53m
No alerts
Replay Analysis
N76517BOEING Boeing 737-800
→
06/10/2026
1h 29m
No alerts
Replay Analysis
N27253BOEING Boeing 737 MAX 8
→
06/09/2026
5h 41m
No alerts
Replay Analysis
N27503BOEING Boeing 737 MAX 9
→
06/07/2026
1h 3m
No alerts
Replay Analysis
N54525AIRBUS Airbus A321 Neo
→
06/07/2026
2h 33m
No alerts
Replay Analysis
N54525AIRBUS Airbus A321 Neo
→
06/06/2026
1h 6m
No alerts
Replay Analysis
N54525AIRBUS Airbus A321 Neo
→
06/06/2026
3h 40m
No alerts
Replay Analysis
© SkyMeter · All flight data subject to ODbL attribution · Tracked: 90-day window