Carrier route record
WNISP→MCO
Southwest Airlines · Islip to Orlando
- Flights
- 678
- Period
- July 2025 to June 2026
- Share of route
- 47%
- Carriers
- 3
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on ISP to MCO sits in the middle of the pack with a C. Close to three flights in four arrive on time by the DOT's definition, 4 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 678 flights. The strongest carrier on the route with a full sample, JetBlue Airways, flew 374 at 74.5% on time.
The national on-time rate over the same period is 77.6%, so Southwest on ISP to MCO runs 4 points behind the country as a whole. Across a thousand flights that is about 42 extra late arrivals.
Key figures
On time
73.4%
Arrivals under 15 minutes late, of 666 completed flights
Avg delay
62 min
Across delayed arrivals only, not all flights
Cancelled
1.47%
National rate is 1.81%
Whole route
72.8%
Every carrier on ISP to MCO, 1,428 flights
These figures cover 678 flights between July 2025 and June 2026. Beyond the headline rate, 9.8% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
Southwest against every carrier on ISP to MCO
Southwest flew 678 of the 1,428 flights on ISP to MCO, about 47% of it. Its 73.4% on time is about level with the route as a whole at 72.8%. Ranked by on-time rate it is number two of three carriers on the route, where the range runs from JetBlue at 74.5% to Frontier at 69.9%.
The two carriers here are closely matched: 5 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| JetBlue Airways | 374 | 74.5% | 75 min | 1.60% | C |
| Southwest Airlines (this page) | 678 | 73.4% | 62 min | 1.47% | C |
| Frontier Airlines | 376 | 69.9% | 97 min | 2.93% | C |
No carrier stands out. JetBlue tops the table at 74.5%, 5 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Departure window
When Southwest runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 44 points, against 5 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am307 flights90.5%
- 8am–11am40 flights86.8%
- 11am–2pm46 flights79.5%
- 2pm–5pm105 flights60.2%
- 5pm–8pm180 flights46.9%
- 8pm–5am—
Scale runs 40% to 95%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 46.9% on time, against 90.5% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 5am–8am window is the busiest, with 307 flights scheduled in it.
Across the year
Southwest on ISP to MCO through the year
October is the best month on the calendar at 85.7% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. May was the busiest month here, with 66 flights.
Across the week, Tuesday is the strongest day at 81.8% on time and Friday the weakest at 64.9%. 17 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Southwest runs late on this route
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 11,000 reported delay minutes.
- 36%Late-arriving aircraft
- 30%Carrier
- 30%National Airspace System
- 3%Extreme weather
36% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 11,000 reported delay minutes here, that single category outweighs weather by 12 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 10,953 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 90.5% on time here.
Cancellations sit at 1.47% against a national 1.81%, which is ordinary. Diversions add another 0.29%.
Connections and stage length
What a delay here costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.8% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
The 971 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg is a different operation and performs like one: it runs 67.1% on time across 677 flights, 6 points below this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 6 points of difference.
One caution: this is a thin sample. 678 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking Southwest on ISP to MCO
Put together: treat all of this as provisional. 678 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 73.4% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 666 completed flights over 12 months sit behind that.
Related
Where to go next
- ISP to MCO, every carrier
- Southwest on MCO to ISP, the return leg
- JetBlue Airways on ISP to MCO74.5%
- Frontier Airlines on ISP to MCO69.9%
- Southwest Airlines network-wide record
- Orlando International (MCO) delay statistics
- Why the first flight of the morning is statistically safest
- How often a connection fails at the major US hubs
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.