Carrier route record
DLBNA→BOS
Delta Air Lines · Nashville to Boston
- Flights
- 533
- Period
- July 2025 to June 2026
- Share of route
- 18%
- Carriers
- 6
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Delta Air Lines.
Delta on BNA to BOS sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 6 points worse than the national rate of 77.6%. The late ones land close to two hours behind schedule. That rests on 533 flights. The strongest carrier on the route with a full sample, Republic Airways, flew 500 at 80.9% on time.
Republic Airways is the most reliable of the three carriers covered here at 80.9% on time across 500 flights.
Key figures
On time
71.5%
Arrivals under 15 minutes late, of 527 completed flights
Avg delay
105 min
Across delayed arrivals only, not all flights
Cancelled
0.75%
National rate is 1.81%
Whole route
69.0%
Every carrier on BNA to BOS, 2,946 flights
These figures cover 533 flights between July 2025 and June 2026. Beyond the headline rate, 14.8% 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
Delta against every carrier on BNA to BOS
Delta flew 533 of the 2,946 flights on BNA to BOS, about 18% of it. Its 71.5% on time is 3 points better than the route as a whole, which runs 69.0%. Ranked by on-time rate it is number three of six carriers on the route, where the range runs from American at 100.0% to Southwest at 60.6%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The choice of carrier is not cosmetic here. Republic Airways arrives on time 80.9% of the time; Southwest Airlines manages 60.6%. Sample sizes sit next to every figure, because a two-point gap across 997 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| American Airlinesthin sample | 2 | 100.0% | — | 0.00% | A+ |
| Republic Airways | 500 | 80.9% | 90 min | 3.60% | B− |
| Delta Air Lines (this page) | 533 | 71.5% | 105 min | 0.75% | C+ |
| JetBlue Airways | 874 | 70.5% | 70 min | 2.29% | C |
| Spirit Airlinesthin sample | 40 | 65.8% | 125 min | 5.00% | C− |
| Southwest Airlines | 997 | 60.6% | 53 min | 1.40% | D |
Republic Airways cancels 3.6% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.
Departure window
When Delta runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 31 points, against 20 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am88 flights94.3%
- 8am–11am18 flights—
- 11am–2pm204 flights70.5%
- 2pm–5pm9 flights—
- 5pm–8pm214 flights62.9%
- 8pm–5am—
Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 62.9% on time, against 94.3% 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 5pm–8pm window is the busiest, with 214 flights scheduled in it.
Across the year
Delta on BNA to BOS through the year
Delays peak in October, when the on-time rate falls to 47.3%. August is the strongest month at 86.1%. Moving a flexible trip across that boundary buys 39 points. May was the busiest month here, with 81 flights.
Across the week, Saturday is the strongest day at 92.0% on time and Friday the weakest at 60.3%. 32 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. Late-arriving aircraft accounts for 43% of the 16,000 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.
- 43%Late-arriving aircraft
- 34%Carrier
- 23%National Airspace System
- 1%Extreme weather
43% 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 16,000 reported delay minutes here, that single category outweighs weather by 43 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 15,784 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 94.3% on time here.
Cancellations are rare at 0.75%, 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 costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 14.8% 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 942 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 71.6% on time across 533 flights, within half a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
One caution: this is a thin sample. 533 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 BNA to BOS
Put together: treat all of this as provisional. 533 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 71.5% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 527 completed flights over 12 months sit behind that.
Related
Where to go next
- BNA to BOS, every carrier
- Delta on BOS to BNA, the return leg
- Republic Airways on BNA to BOS80.9%
- JetBlue Airways on BNA to BOS70.5%
- Southwest Airlines on BNA to BOS60.6%
- Delta Air Lines network-wide record
- Nashville International (BNA) delay statistics
- Boston Logan International (BOS) delay statistics
- Same route, different airline: where the carrier you pick matters most
- Why the first flight of the morning is statistically safest
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.