Route reliability record

MCO→STL

Orlando to St. Louis

Flights: 2,485
Period: July 2025 to June 2026
Distance: 882 mi
Carriers: 3

This route lands a B+, level with the national rate of 77.6%. Roughly one flight in four arrive 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 2,485 flights, of which Southwest Airlines flew 2,081 at 77.6% on time.

The US average over the same twelve months is 77.6%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

On time

77.0%

Arrivals under 15 minutes late, of 2,457 completed flights

Avg delay

69 min

Across delayed arrivals only, not all flights

Cancelled

0.80%

National rate is 1.81%

Best carrier

Southwest

77.6% on time across 2,081 flights

These figures cover 2,485 flights between July 2025 and June 2026. Beyond the headline rate, 8.8% 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

Which airline is most reliable on MCO to STL

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.

On-time performance by carrier on MCO to STL
Airline	Flights	On time	Avg delay	Cancelled	Grade
Spirit Airlinesthin sample	10	100.0%	—	0.00%	A+
Southwest Airlines	2,081	77.6%	62 min	0.72%	B+
Frontier Airlines	394	72.9%	97 min	1.27%	C

No carrier stands out. Southwest tops the table at 77.6%, 5 points clear of the bottom, which is inside the range this kind of sample moves year to year.

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 32 points, against 5 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am289 flights94.4%
8am–11am484 flights92.5%
11am–2pm331 flights81.8%
2pm–5pm358 flights71.4%
5pm–8pm456 flights67.5%
8pm–5am567 flights62.7%

Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 62.7% on time, against 94.4% 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 8pm–5am window is the busiest, with 567 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 21 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.

Darker means more delays. Figures are on-time percentages.September best, August worst

August is the worst month at 68.0% on time, 21 points below September, the best at 88.5%. 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. March was the busiest month here, with 265 flights.

Across the week, Wednesday is the strongest day at 87.4% on time and Sunday the weakest at 68.9%. 19 points is a smaller lever than departure hour, but it is free.

Delay causes

Why this route gets delayed

One category carries most of the weight here. Late-arriving aircraft accounts for 49% of the 39,000 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
49%
Carrier
35%
National Airspace System
11%
Extreme weather
5%
Security
1%

49% 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 39,000 reported delay minutes here, that single category outweighs weather by 9 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 38,795 reported delay minutes.

The largest share of delay minutes, 35%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 14,000 of the 39,000 delay minutes reported here.

Cancellations are rare at 0.80%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.

Connections and stage length

What a delay here actually costs

8.8% 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 are the a little over an hour kind, which a normal layover absorbs.

The 882 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 78.0% on time across 2,497 flights, within about a point 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 2,485 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.

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 88.5% on time and August 68.0%, a swing of 21 points. If the dates move at all, move them out of August before you think about anything else. 2,457 completed flights over 12 months sit behind that.

Common questions

MCO to STL questions

How often is MCO to STL delayed?

Roughly one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 23.0% of the 2,485 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.

Which airline is most reliable on MCO to STL?

Southwest Airlines leads at 77.6% on time across 2,081 flights. Frontier Airlines is at the other end on 72.9%, a gap of 5 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 STL?

The 5am–8am departure window is the strongest at 94.4% on time. The 8pm–5am window is the weakest at 62.7%, 32 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 August delays on MCO to STL?

August is the weakest month at 68.0% on time, compared with 88.5% in September. Across the year that is 21 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.

Where to go next

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

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.

Key figures