Route reliability record

BOS→BNA

Boston to Nashville

Flights: 2,945
Period: July 2025 to June 2026
Distance: 942 mi
Carriers: 6

This route sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 7 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 2,945 flights, of which JetBlue Airways flew 874 at 72.1% on time.

JetBlue Airways is the most reliable of the four carriers covered here at 72.1% on time across 874 flights.

On time

70.4%

Arrivals under 15 minutes late, of 2,882 completed flights

Avg delay

68 min

Across delayed arrivals only, not all flights

Cancelled

1.87%

National rate is 1.81%

Best carrier

JetBlue

72.1% on time across 874 flights

These figures cover 2,945 flights between July 2025 and June 2026. Beyond the headline rate, 11.2% 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 BOS to BNA

The four 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 BOS to BNA
Airline	Flights	On time	Avg delay	Cancelled	Grade
American Airlinesthin sample	2	100.0%	—	0.00%	A+
Spirit Airlinesthin sample	40	86.8%	109 min	2.50%	A
JetBlue Airways	874	72.1%	64 min	2.06%	C
Delta Air Lines	533	71.6%	88 min	0.75%	C+
Republic Airways	500	71.5%	71 min	4.00%	C−
Southwest Airlines	996	67.0%	61 min	1.20%	C

Republic Airways cancels 4.0% 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

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

5am–8am433 flights86.8%
8am–11am729 flights81.4%
11am–2pm267 flights75.8%
2pm–5pm606 flights62.3%
5pm–8pm614 flights56.2%
8pm–5am296 flights60.1%

Scale runs 50% to 90%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 56.2% on time, against 86.8% 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 729 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 20 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.August best, June worst

June is the worst month at 63.5% on time, 20 points below August, the best at 83.0%. 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. October was the busiest month here, with 330 flights.

Across the week, Saturday is the strongest day at 78.1% on time and Thursday the weakest at 64.7%. 13 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 47% of the 58,000 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
47%
Carrier
34%
National Airspace System
17%
Extreme weather
2%
Security
0%

47% 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 58,000 reported delay minutes here, that single category outweighs weather by 28 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 58,269 reported delay minutes.

The largest share of delay minutes, 34%, 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 20,000 of the 58,000 delay minutes reported here.

Cancellations sit at 1.87% against a national 1.81%, which is ordinary. Diversions add another 0.27%.

Connections and stage length

What a delay here actually costs

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 11.2% 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 69.0% on time across 2,946 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 2,945 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. August runs 83.0% on time and June 63.5%, a swing of 20 points. If the dates move at all, move them out of June before you think about anything else. 2,882 completed flights over 12 months sit behind that.

Common questions

BOS to BNA questions

How often is BOS to BNA delayed?

Roughly one flight in three arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 29.6% of the 2,945 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 BOS to BNA?

JetBlue Airways leads at 72.1% on time across 874 flights. Southwest Airlines is at the other end on 67.0%, 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 BOS to BNA?

The 5am–8am departure window is the strongest at 86.8% on time. The 5pm–8pm window is the weakest at 56.2%, 31 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 June delays on BOS to BNA?

June is the weakest month at 63.5% on time, compared with 83.0% in August. Across the year that is 20 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. BOS to BNA and BNA to BOS 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