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Flight WN3521

Southwest Airlines flight WN3521

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Looking for WN3521 in the air…

Chicago (MDW) to Seattle (SEA)

Historically, this flight arrives 15+ minutes late 19% of the time, and when it is late the delay averages 39 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
39 min
Flights arriving 15+ minutes late
Flights tracked
58
Scheduled flights in the period

What caused the delays

  • Airline (crew, maintenance, cleaning) 58%
  • Air traffic control & airport 31%
  • Late-arriving aircraft 11%
  • Extreme weather 0%
  • Security 0%

Share of delay minutes airlines attributed to each cause (BTS).

Kansas City (MCI) to Las Vegas (LAS)

Historically, this flight arrives 15+ minutes late 42% of the time, and when it is late the delay averages 64 minutes. It was cancelled 0.0% of the time.

On-time arrivals
58.3%
Less than 15 minutes late
Cancelled
0.0%
Of scheduled flights
Average delay when late
64 min
Flights arriving 15+ minutes late
Flights tracked
36
Scheduled flights in the period

What caused the delays

  • Late-arriving aircraft 80%
  • Air traffic control & airport 9%
  • Airline (crew, maintenance, cleaning) 8%
  • Extreme weather 3%
  • Security 0%

Share of delay minutes airlines attributed to each cause (BTS).

Los Angeles (LAX) to San Jose (SJC)

Historically, this flight arrives 15+ minutes late 22% of the time, and when it is late the delay averages 56 minutes. It was cancelled 0.0% of the time.

On-time arrivals
77.8%
Less than 15 minutes late
Cancelled
0.0%
Of scheduled flights
Average delay when late
56 min
Flights arriving 15+ minutes late
Flights tracked
27
Scheduled flights in the period

What caused the delays

  • Late-arriving aircraft 96%
  • Airline (crew, maintenance, cleaning) 4%
  • Air traffic control & airport 0%
  • Extreme weather 0%
  • Security 0%

Share of delay minutes airlines attributed to each cause (BTS).

Los Angeles (LAX) to Phoenix (PHX)

Only 16 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
16
Scheduled flights in the period

Sacramento (SMF) to Los Angeles (LAX)

Only 16 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
16
Scheduled flights in the period

St Louis (STL) to Panama City Beach (ECP)

Only 12 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
59 min
Flights arriving 15+ minutes late
Flights tracked
12
Scheduled flights in the period

What caused the delays

  • Late-arriving aircraft 59%
  • Airline (crew, maintenance, cleaning) 41%
  • Air traffic control & airport 0%
  • Extreme weather 0%
  • Security 0%

Share of delay minutes airlines attributed to each cause (BTS).

Chicago (MDW) to Boston (BOS)

Only 9 flights on record, which is too few for reliable odds.

On-time arrivals
55.6%
Less than 15 minutes late
Cancelled
0.0%
Of scheduled flights
Average delay when late
98 min
Flights arriving 15+ minutes late
Flights tracked
9
Scheduled flights in the period

What caused the delays

  • Air traffic control & airport 53%
  • Late-arriving aircraft 43%
  • Airline (crew, maintenance, cleaning) 4%
  • Extreme weather 0%
  • Security 0%

Share of delay minutes airlines attributed to each cause (BTS).

Atlanta (ATL) to Houston (HOU)

Only 8 flights on record, which is too few for reliable odds.

On-time arrivals
75.0%
Less than 15 minutes late
Cancelled
0.0%
Of scheduled flights
Average delay when late
115 min
Flights arriving 15+ minutes late
Flights tracked
8
Scheduled flights in the period

What caused the delays

  • Late-arriving aircraft 91%
  • Airline (crew, maintenance, cleaning) 9%
  • Air traffic control & airport 0%
  • Extreme weather 0%
  • Security 0%

Share of delay minutes airlines attributed to each cause (BTS).

Las Vegas (LAS) to Baltimore (BWI)

Only 8 flights on record, which is too few for reliable odds.

On-time arrivals
87.5%
Less than 15 minutes late
Cancelled
0.0%
Of scheduled flights
Average delay when late
25 min
Flights arriving 15+ minutes late
Flights tracked
8
Scheduled flights in the period

What caused the delays

  • Air traffic control & airport 61%
  • Airline (crew, maintenance, cleaning) 39%
  • Late-arriving aircraft 0%
  • Extreme weather 0%
  • Security 0%

Share of delay minutes airlines attributed to each cause (BTS).

Sarasota/Bradenton (SRQ) to Orlando (MCO)

Only 8 flights on record, which is too few for reliable odds.

On-time arrivals
37.5%
Less than 15 minutes late
Cancelled
0.0%
Of scheduled flights
Average delay when late
111 min
Flights arriving 15+ minutes late
Flights tracked
8
Scheduled flights in the period

What caused the delays

  • Air traffic control & airport 64%
  • Airline (crew, maintenance, cleaning) 36%
  • Late-arriving aircraft 1%
  • Extreme weather 0%
  • Security 0%

Share of delay minutes airlines attributed to each cause (BTS).

Tampa (TPA) to Atlanta (ATL)

Only 8 flights on record, which is too few for reliable odds.

On-time arrivals
75.0%
Less than 15 minutes late
Cancelled
0.0%
Of scheduled flights
Average delay when late
110 min
Flights arriving 15+ minutes late
Flights tracked
8
Scheduled flights in the period

What caused the delays

  • Airline (crew, maintenance, cleaning) 72%
  • Air traffic control & airport 15%
  • Late-arriving aircraft 13%
  • Extreme weather 0%
  • Security 0%

Share of delay minutes airlines attributed to each cause (BTS).

Las Vegas (LAS) to Ontario (ONT)

Only 7 flights on record, which is too few for reliable odds.

On-time arrivals
42.9%
Less than 15 minutes late
Cancelled
0.0%
Of scheduled flights
Average delay when late
35 min
Flights arriving 15+ minutes late
Flights tracked
7
Scheduled flights in the period

What caused the delays

  • Late-arriving aircraft 43%
  • Airline (crew, maintenance, cleaning) 36%
  • Air traffic control & airport 21%
  • Extreme weather 0%
  • Security 0%

Share of delay minutes airlines attributed to each cause (BTS).

Seattle (SEA) to Las Vegas (LAS)

Only 7 flights on record, which is too few for reliable odds.

On-time arrivals
71.4%
Less than 15 minutes late
Cancelled
0.0%
Of scheduled flights
Average delay when late
29 min
Flights arriving 15+ minutes late
Flights tracked
7
Scheduled flights in the period

What caused the delays

  • Airline (crew, maintenance, cleaning) 51%
  • Late-arriving aircraft 24%
  • Air traffic control & airport 24%
  • Extreme weather 0%
  • Security 0%

Share of delay minutes airlines attributed to each cause (BTS).

Las Vegas (LAS) to Los Angeles (LAX)

Only 5 flights on record, which is too few for reliable odds.

On-time arrivals
80.0%
Less than 15 minutes late
Cancelled
0.0%
Of scheduled flights
Average delay when late
44 min
Flights arriving 15+ minutes late
Flights tracked
5
Scheduled flights in the period

What caused the delays

  • Late-arriving aircraft 80%
  • Airline (crew, maintenance, cleaning) 20%
  • Air traffic control & airport 0%
  • Extreme weather 0%
  • Security 0%

Share of delay minutes airlines attributed to each cause (BTS).

PBI → BWI

Only 5 flights on record, which is too few for reliable odds.

On-time arrivals
60.0%
Less than 15 minutes late
Cancelled
0.0%
Of scheduled flights
Average delay when late
28 min
Flights arriving 15+ minutes late
Flights tracked
5
Scheduled flights in the period

What caused the delays

  • Late-arriving aircraft 58%
  • Air traffic control & airport 24%
  • Airline (crew, maintenance, cleaning) 18%
  • Extreme weather 0%
  • Security 0%

Share of delay minutes airlines attributed to each cause (BTS).

Dallas (DAL) to Memphis (MEM)

Only 4 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
4
Scheduled flights in the period

El Paso (ELP) to Los Angeles (LAX)

Only 4 flights on record, which is too few for reliable odds.

On-time arrivals
25.0%
Less than 15 minutes late
Cancelled
0.0%
Of scheduled flights
Average delay when late
39 min
Flights arriving 15+ minutes late
Flights tracked
4
Scheduled flights in the period

What caused the delays

  • Air traffic control & airport 47%
  • Late-arriving aircraft 31%
  • Airline (crew, maintenance, cleaning) 22%
  • Extreme weather 0%
  • Security 0%

Share of delay minutes airlines attributed to each cause (BTS).

Houston (HOU) to El Paso (ELP)

Only 4 flights on record, which is too few for reliable odds.

On-time arrivals
75.0%
Less than 15 minutes late
Cancelled
0.0%
Of scheduled flights
Average delay when late
32 min
Flights arriving 15+ minutes late
Flights tracked
4
Scheduled flights in the period

What caused the delays

  • Late-arriving aircraft 86%
  • Airline (crew, maintenance, cleaning) 14%
  • Air traffic control & airport 0%
  • Extreme weather 0%
  • Security 0%

Share of delay minutes airlines attributed to each cause (BTS).

Tampa (TPA) to Los Angeles (LAX)

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

Kansas City (MCI) to Los Angeles (LAX)

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

In the news

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On-time arrivals by month
Sep 2025 Aug 2026
Show as table
MonthOn timeFlights
September 2025 100.0% 4
October 2025 71.8% 39
November 2025 63.2% 19
December 2025 60.0% 15
January 2026 50.0% 4
February 2026 100.0% 3
March 2026 81.8% 11
April 2026 78.1% 32
May 2026 71.8% 39
June 2026 82.8% 29
July 2026 100.0% 28
August 2026 47.8% 23

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

Latest airport & airline headlines

More headlines →

Headlines found by Google News; stories open on the publisher's site.