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ATIS Alerts Smart Flight Search

Find the flight least likely to be delayed

Beta

We rank real flight numbers by how often they flew and arrived on time over the last 12 months, adjusted for your travel month and departure time, then check nearby airports and calmer connections. US airlines and airports.

ISP → BWI

Islip to Baltimore: 1,201 nonstop flights a year

On time (12 months)

84%

Cancelled

1.4%

avg delay 11 min

Best time to leave

Before 9 AM

96% on time vs 77% noon to 3 PM

Most reliable airline

Southwest

83% chance on time

Check ISP to BWI fares

Fares open on our travel partner (Aviasales). Pick the flight number you chose here.

Most reliable nonstop flights

Ranked by the chance the flight operates and arrives within 15 minutes of schedule, from Jun 2025 to May 2026 records.

  1. #1 · Southwest 2160

    6:00 AM → 7:20 AM1h 20m nonstop

    Local times, typical schedule. Last flown 2026-05-31. Same departure also flew as Southwest 1187; its record covers all of them.

    95%

    chance on time

    On time (history)
    99%
    Cancelled
    1.1%
    Avg arrival delay
    5 min
    • Arrived on time 99% of the time (87 flights, Jun 2025 to May 2026).
    • Leaves in this route's most on-time window (Before 9 AM: 96% on time; Noon to 3 PM: 77%).

    Moderate track record · 87 flights

    Find Southwest 2160 fares Opens this date on Aviasales

  2. #2 · Southwest 1076

    9:00 AM → 10:20 AM1h 20m nonstop

    Local times, typical schedule. Last flown 2026-05-27.

    90%

    chance on time

    On time (history)
    100%
    Cancelled
    0.0%
    Avg arrival delay
    1 min
    • Arrived on time 100% of the time (16 flights, Jun 2025 to May 2026).
    • Short track record (16 flights), so its score leans on the airline's record at this hour.

    Limited track record · 16 flights

    Find Southwest 1076 fares Opens this date on Aviasales

  3. #3 · Southwest 1077

    8:35 AM → 9:55 AM1h 20m nonstop

    Local times, typical schedule. Last flown 2026-05-29.

    88%

    chance on time

    On time (history)
    96%
    Cancelled
    0.0%
    Avg arrival delay
    3 min
    • Arrived on time 96% of the time (23 flights, Jun 2025 to May 2026).
    • Leaves in this route's most on-time window (Before 9 AM: 96% on time; Noon to 3 PM: 77%).
    • Short track record (23 flights), so its score leans on the airline's record at this hour.

    Limited track record · 23 flights

    Find Southwest 1077 fares Opens this date on Aviasales

  4. #4 · Southwest 3215

    4:40 PM → 6:00 PM1h 20m nonstop

    Local times, typical schedule. Last flown 2026-05-30.

    86%

    chance on time

    On time (history)
    100%
    Cancelled
    0.0%
    Avg arrival delay
    1 min
    • Arrived on time 100% of the time (8 flights, Jun 2025 to May 2026).
    • Lands inside BWI's trouble window: 81% of its 43 ground stops and delay programs started between 2 PM and 8 PM.
    • Short track record (8 flights), so its score leans on the airline's record at this hour.

    Limited track record · 8 flights

    Find Southwest 3215 fares Opens this date on Aviasales

  5. #5 · Southwest 1257

    4:30 PM → 5:50 PM1h 20m nonstop

    Local times, typical schedule. Last flown 2026-05-29.

    85%

    chance on time

    On time (history)
    91%
    Cancelled
    0.0%
    Avg arrival delay
    5 min
    • Arrived on time 91% of the time (23 flights, Jun 2025 to May 2026).
    • Lands inside BWI's trouble window: 81% of its 43 ground stops and delay programs started between 2 PM and 8 PM.
    • Short track record (23 flights), so its score leans on the airline's record at this hour.

    Limited track record · 23 flights

    Find Southwest 1257 fares Opens this date on Aviasales

  6. #6 · Southwest 3081

    12:30 PM → 1:45 PM1h 15m nonstop

    Local times, typical schedule. Last flown 2026-05-29.

    82%

    chance on time

    On time (history)
    87%
    Cancelled
    0.0%
    Avg arrival delay
    6 min
    • Arrived on time 87% of the time (39 flights, Jun 2025 to May 2026).
    • Never cancelled in 39 scheduled flights.
    • Leaves in this route's least on-time window (Noon to 3 PM: 77% on time; Before 9 AM: 96%).
    • Short track record (39 flights), so its score leans on the airline's record at this hour.

    Limited track record · 39 flights

    Find Southwest 3081 fares Opens this date on Aviasales

  7. #7 · Southwest 993

    4:10 PM → 5:30 PM1h 20m nonstop

    Local times, typical schedule. Last flown 2026-05-31.

    81%

    chance on time

    On time (history)
    84%
    Cancelled
    0.0%
    Avg arrival delay
    13 min
    • Arrived on time 84% of the time (32 flights, Jun 2025 to May 2026).
    • Never cancelled in 32 scheduled flights.
    • Lands inside BWI's trouble window: 81% of its 43 ground stops and delay programs started between 2 PM and 8 PM.
    • 74% of its delay minutes came from the plane arriving late from an earlier flight.

    Limited track record · 32 flights

    Find Southwest 993 fares Opens this date on Aviasales

  8. #8 · Southwest 2939

    5:55 PM → 7:15 PM1h 20m nonstop

    Local times, typical schedule. Last flown 2026-04-05.

    73%

    chance on time

    On time (history)
    66%
    Cancelled
    6.3%
    Avg arrival delay
    15 min
    • Arrived on time 66% of the time (29 flights, Jun 2025 to May 2026).
    • Cancelled 6.3% of the time (2 of 32).
    • Lands inside BWI's trouble window: 81% of its 43 ground stops and delay programs started between 2 PM and 8 PM.
    • 85% of its delay minutes came from the plane arriving late from an earlier flight.

    Limited track record · 29 flights

    Find Southwest 2939 fares Opens this date on Aviasales

  9. #9 · Southwest 1744

    2:00 PM → 3:15 PM1h 15m nonstop

    Local times, typical schedule. Last flown 2026-04-06.

    69%

    chance on time

    On time (history)
    57%
    Cancelled
    0.0%
    Avg arrival delay
    23 min
    • Arrived on time 57% of the time (23 flights, Jun 2025 to May 2026).
    • Leaves in this route's least on-time window (Noon to 3 PM: 77% on time; Before 9 AM: 96%).
    • Lands inside BWI's trouble window: 81% of its 43 ground stops and delay programs started between 2 PM and 8 PM.
    • 52% of its delay minutes came from the plane arriving late from an earlier flight.

    Limited track record · 23 flights

    Find Southwest 1744 fares Opens this date on Aviasales

Airlines on this route

Season-adjusted chance of operating and arriving on time.

  • Southwest Airlines83%

    1,201 flights · 84% on time as flown · 1.4% cancel

On time by departure time

All airlines, scheduled local departure, Jun 2025 to May 2026.

  • Before 9 AM96%

    391 flights · avg delay 4 min

  • 9 AM to noon87%

    159 flights · avg delay 5 min

  • Noon to 3 PM77%

    289 flights · avg delay 15 min

  • 3 to 6 PM78%

    355 flights · avg delay 20 min

Best day: Tuesday (88%). Worst: Friday (83%).

Historical odds, not a guarantee. Built from the US DOT Bureau of Transportation Statistics on-time reports (Jun 2025 to May 2026), FAA ground stop and delay program advisories, and 20 years of airport weather observations. Covers US airlines that report to the DOT; schedules are flights operated recently, so confirm times when you book. ATIS Alerts is not affiliated with any airline. Fares are what Aviasales travelers saw in recent searches (USD, one way, 1 adult), not live quotes; the partner site shows the current price. Fare links go to our travel partner and may earn us a commission at no cost to you. Affiliate disclosure