Carrier route record

DLMSY→BOS

Delta Air Lines · New Orleans to Boston

Flights: 372
Period: July 2025 to June 2026
Share of route: 44%
Carriers: 4

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Delta Air Lines.

Delta on MSY to BOS draws a D. Roughly one flight in three arrives at least 15 minutes late, and the typical late arrival is a little over an hour behind schedule. Build slack into anything you connect to. That rests on 372 flights, with a median arrival 2 minutes late.

The national on-time rate over the same period is 77.6%, so Delta on MSY to BOS runs 14 points behind the country as a whole. Across a thousand flights that is about 139 extra late arrivals.

On time

63.7%

Arrivals under 15 minutes late, of 364 completed flights

Avg delay

75 min

Across delayed arrivals only, not all flights

Cancelled

2.15%

National rate is 1.81%

Whole route

62.7%

Every carrier on MSY to BOS, 853 flights

These figures cover 372 flights between July 2025 and June 2026. Beyond the headline rate, 15.1% 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

Delta against every carrier on MSY to BOS

Delta flew 372 of the 853 flights on MSY to BOS, about 44% of it. Its 63.7% on time is about level with the route as a whole at 62.7%. Ranked by on-time rate it is number two of four carriers on the route, where the range runs from American at 100.0% to Spirit at 50.0%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.

Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.

On-time performance by carrier on MSY to BOS
Airline	Flights	On time	Avg delay	Cancelled	Grade
American Airlinesthin sample	2	100.0%	—	0.00%	A+
Delta Air Lines (this page)	372	63.7%	75 min	2.15%	D
JetBlue Airways	471	62.0%	93 min	1.70%	D
Spirit Airlinesthin sample	8	50.0%	39 min	0.00%	F+

Departure window

When Delta runs best on this route

Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 372 flights.

There are not enough flights in each departure window to split Delta's MSY to BOS record by time of day without the percentages moving on noise. The headline rate of 63.7% is the reliable figure here.

Across the year

Delta on MSY to BOS through the year

Darker means more delays. Figures are on-time percentages.December best, July worst

July is the worst month at 48.4% on time, 35 points below December, the best at 83.3%. 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. April was the busiest month here, with 35 flights.

Across the week, Saturday is the strongest day at 75.9% on time and Thursday the weakest at 52.9%. 23 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Delta runs late on this route

One category carries most of the weight here. National Airspace System accounts for 54% of the 9,881 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.

National Airspace System
54%
Late-arriving aircraft
28%
Carrier
15%
Extreme weather
3%
Security
0%

54% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 5,286 minutes out of 9,881, against a national NAS share of 21%. The split is drawn from 9,881 reported delay minutes.

Cancellations sit at 2.15% against a national 1.81%, which is ordinary. Diversions add another 0.00%.

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. 15.1% 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 1,367 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 84.1% on time across 374 flights, 20 points above 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 20 points of difference.

One caution: this is a thin sample. 372 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 Delta on MSY to BOS

Put together: treat all of this as provisional. 372 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 63.7% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 364 completed flights over 12 months sit behind that.

Where to go next

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.

Key figures