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DelayAtlas

Route reliability record

MCOISP

Orlando to Islip

Flights
1,427
Period
July 2025 to June 2026
Distance
971 mi
Carriers
3
CGRADE

This route sits in the middle of the pack with a C. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 1,427 MCO to ISP flights, of which JetBlue Airways flew 374 at 88.3% on time.

Best time to fly MCO to ISP: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 93.7% of the time and Tuesday flights 86.7%, against 74.8% for the route overall.

JetBlue Airways is the most reliable of the three carriers covered here at 88.3% on time across 374 flights.

Key figures

On time

74.8%

Arrivals under 15 minutes late, of 1,399 completed flights

Avg delay

59 min

Across delayed arrivals only, not all flights

Cancelled

1.75%

National rate is 1.81%

Best carrier

JetBlue

88.3% on time across 374 flights

These figures cover 1,427 flights between July 2025 and June 2026. The median arrival is 3 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.

Carrier by carrier

Which airline is most reliable on MCO to ISP

The choice of carrier is not cosmetic here. JetBlue Airways arrives on time 88.3% of the time; Southwest Airlines manages 67.1%. Sample sizes sit next to every figure, because a two-point gap across 677 flights means less than a ten-point one.

On-time performance by carrier on MCO to ISP
AirlineFlightsOn timeAvg delayCancelledGrade
JetBlue Airways37488.3%55 min1.34%A
Frontier Airlines37675.1%81 min2.39%B
Southwest Airlines67767.1%51 min1.62%C

The spread between JetBlue and Southwest is 21 points, wide enough that it should decide the booking. On a hundred trips that is 21 more arrivals inside the on-time window.

Flight by flight

Flights on MCO to ISP

The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.

Best ways to make this trip

The most reliable ways to fly Orlando to Islip

Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 3 of the top 5 use a different airport at one end.

Most reliable ways to fly from MCO to ISP
OptionAirlineSuccessOn timeCancelledBest departureMost punctual flight
1. MCOISPOrlando to IslipJetBlue Airways87.1%88.3%1.34%5am–8am, TueB6 546 06:15
2. MCOEWROrlando to NewarkUnited Airlines76.6%78.1%1.97%5am–8am, WedUA 370 08:00
3. MCOJFKOrlando to New YorkDelta Air Lines75.8%78.1%2.93%5am–8am, WedDL 2702 06:00
4. MCOISPOrlando to IslipFrontier Airlines73.3%75.1%2.39%5am–8am, Tue
5. MCOLGAOrlando to New YorkDelta Air Lines72.6%76.0%4.42%5am–8am, WedDL 1523 07:05

Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.

Plan this trip by month, day and time

Departure window

The best time of day to leave

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 41 points, against 21 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am293 flights93.7%
  • 8am–11am374 flights84.6%
  • 11am–2pm200 flights73.4%
  • 2pm–5pm130 flights68.3%
  • 5pm–8pm229 flights58.3%
  • 8pm–5am201 flights53.1%

Scale runs 45% to 100%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 53.1% on time, against 93.7% 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 8am–11am window is the busiest, with 374 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 24 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.

On-time rate by calendar month83J73F66M74A78M75J65J71A89S75O85N67D
Darker means more delays. Figures are on-time percentages.September best, July worst

July is the worst month at 64.5% on time, 24 points below September, the best at 88.8%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. December was the busiest month here, with 133 flights.

Across the week, Tuesday is the strongest day at 86.7% on time and Sunday the weakest at 69.5%. 17 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week72.3Mon86.7Tue78.4Wed72.3Thu74.5Fri71.7Sat69.5Sun
Monday: 72.3 percent on time. Tuesday: 86.7 percent on time. Wednesday: 78.4 percent on time. Thursday: 72.3 percent on time. Friday: 74.5 percent on time. Saturday: 71.7 percent on time. Sunday: 69.5 percent on time

Delay causes

Why this route gets delayed

One category carries most of the weight here. Late-arriving aircraft accounts for 46% of the 21,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.

  • Late-arriving aircraft
    46%
  • Carrier
    31%
  • National Airspace System
    16%
  • Extreme weather
    8%
  • Security
    0%

46% 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 21,000 reported delay minutes here, that single category outweighs weather by 6 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 20,948 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 93.7% on time here.

Cancellations sit at 1.75% against a national 1.81%, which is ordinary. Diversions add another 0.21%.

Connections and stage length

What a delay here actually costs

7.6% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, which a normal layover absorbs.

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 runs 72.8% on time across 1,428 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

The sample behind these figures is 1,427 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.

Work out the risk of missing a connection in ISP after this flight

What to do with this

Booking this route

Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 88.8% on time and July 64.5%, a swing of 24 points. If the dates move at all, move them out of July before you think about anything else. 1,399 completed flights over 12 months sit behind that.

Common questions

MCO to ISP questions

How often is MCO to ISP delayed?

About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 25.2% of the 1,427 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.

Which airline is most reliable on MCO to ISP?

JetBlue Airways leads at 88.3% on time across 374 flights. Southwest Airlines is at the other end on 67.1%, a gap of 21 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.

What time of day has the fewest delays on MCO to ISP?

The 5am–8am departure window is the strongest at 93.7% on time. The 8pm–5am window is the weakest at 53.1%, 41 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.

How bad are July delays on MCO to ISP?

July is the weakest month at 64.5% on time, compared with 88.8% in September. Across the year that is 24 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.

Related

Where to go next

Direction matters. MCO to ISP and ISP to MCO are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.

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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.