Flight Status & Tracker

UAL521

UNITED AIRLINES INC · IAH → BOS · Last tracked Oct 22, 2026

UAL521 is a flight number operated by UNITED AIRLINES INC between George Bush Intercontinental Houston Airport (KIAH) and General Edward Lawrence Logan International Airport (KBOS). SkyMeter last tracked UAL521 on October 22, 2026. The flight is most often flown by a BOEING Boeing 737 MAX 9. Typical block time is 3h 9m. SkyMeter has observed 79 legs of this flight number via ADS-B.

SkyMeter tracks historical flight activity from ADS-B data — this is not a live gate-to-gate status feed.

✈
FLIGHTS
79
last 90 days
⏱
AVG DURATION
3h 9m
tracked time
📅
SERVICE PERIOD
5/27/2025 → 10/22/2026
first → last seen
🗺
ROUTES / TYPES
5 / 4
city pairs · airframes
⚠
INCIDENT RATE
0.0%
0 flagged

Routes flown

By count · last 90 days

3
KIAH → KBOS
67
avg 3h 20m · George Bush Intercontinental Houston → General Edward Lawrence Logan
KIAH → KMCO
2
avg 2h 2m · George Bush Intercontinental Houston → Orlando
KPWM → KIAH
2
avg 3h 57m · Portland International Jetport → George Bush Intercontinental Houston

Aircraft types

Equipment used on this number

4
B39M BOEING Boeing 737 MAX 9
107
B38M BOEING Boeing 737 MAX 8
5
A319 AIRBUS Airbus A319
4
B739 BOEING Boeing 737-900
2

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 UAL521

30
N57480
→
10/22/2026
3h 21m
No alerts
Replay Analysis
N47505BOEING Boeing 737 MAX 9
→
10/20/2026
3h 13m
No alerts
Replay Analysis
N17591BOEING Boeing 737 MAX 9
→
10/16/2026
3h 7m
No alerts
Replay Analysis
N57466BOEING Boeing 737 MAX 9
→
10/15/2026
3h 5m
No alerts
Replay Analysis
N37535BOEING Boeing 737 MAX 9
→
10/14/2026
3h 7m
No alerts
Replay Analysis
N17338BOEING Boeing 737 MAX 8
→
10/10/2026
2h 3m
No alerts
Replay Analysis
N69838BOEING Boeing 737-900
→
10/10/2026
3h 7m
No alerts
Replay Analysis
N17455BOEING Boeing 737 MAX 9
→
10/9/2026
3h 3m
No alerts
Replay Analysis
N17417BOEING Boeing 737 MAX 9
→
10/8/2026
3h 13m
No alerts
Replay Analysis
N27519BOEING Boeing 737 MAX 9
→
10/7/2026
3h 12m
No alerts
Replay Analysis
N37530BOEING Boeing 737 MAX 9
→
10/6/2026
3h 14m
No alerts
Replay Analysis
N77576BOEING Boeing 737 MAX 9
→
10/5/2026
2h 54m
No alerts
Replay Analysis
N47275BOEING Boeing 737 MAX 8
→
10/3/2026
1h 59m
No alerts
Replay Analysis
N47462BOEING Boeing 737 MAX 9
→
10/3/2026
3h 7m
No alerts
Replay Analysis
N37530BOEING Boeing 737 MAX 9
→
10/2/2026
3h 17m
No alerts
Replay Analysis
N47524BOEING Boeing 737 MAX 9
→
10/1/2026
3h 16m
No alerts
Replay Analysis
N47524BOEING Boeing 737 MAX 9
→
10/1/2026
5m
No alerts
Replay Analysis
N47524BOEING Boeing 737 MAX 9
→
10/1/2026
3h 22m
No alerts
Replay Analysis
N37562BOEING Boeing 737 MAX 9
→
9/30/2026
3h 29m
No alerts
Replay Analysis
N37507BOEING Boeing 737 MAX 9
→
9/29/2026
3h 13m
No alerts
Replay Analysis
N47505BOEING Boeing 737 MAX 9
→
9/28/2026
3h 17m
No alerts
Replay Analysis
N37415BOEING Boeing 737 MAX 9
→
9/26/2026
3h 26m
No alerts
Replay Analysis
N47505BOEING Boeing 737 MAX 9
→
9/25/2026
3h 14m
No alerts
Replay Analysis
N17433BOEING Boeing 737 MAX 9
→
9/24/2026
3h 21m
No alerts
Replay Analysis
N27546BOEING Boeing 737 MAX 9
→
9/23/2026
3h 20m
No alerts
Replay Analysis
N17431BOEING Boeing 737 MAX 9
→
9/22/2026
3h 19m
No alerts
Replay Analysis
N77587BOEING Boeing 737 MAX 9
→
9/21/2026
3h 20m
No alerts
Replay Analysis
N37577BOEING Boeing 737 MAX 9
→
9/20/2026
13m
No alerts
Replay Analysis
N17589BOEING Boeing 737 MAX 9
→
9/19/2026
3h 25m
No alerts
Replay Analysis
N77588BOEING Boeing 737 MAX 9
→
9/18/2026
3h 14m
No alerts
Replay Analysis
© SkyMeter · All flight data subject to ODbL attribution · Tracked: 90-day window