Carrier route record

F9BOS→ATL

Frontier Airlines · Boston to Atlanta

Flights: 399
Period: July 2025 to June 2026
Share of route: 8%
Carriers: 4

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

Frontier on BOS to ATL draws a C−. About one flight in three arrives at least 15 minutes late, and the typical late arrival is roughly 50 minutes behind schedule. Build slack into anything you connect to. That rests on 399 flights. The strongest carrier on the route with a full sample, Delta Air Lines, flew 3,662 at 82.1% on time.

The national on-time rate over the same period is 77.6%, so Frontier on BOS to ATL runs 12 points behind the country as a whole. Across a thousand flights that is about 124 extra late arrivals.

On time

65.2%

Arrivals under 15 minutes late, of 385 completed flights

Avg delay

52 min

Across delayed arrivals only, not all flights

Cancelled

3.26%

National rate is 1.81%

Whole route

78.5%

Every carrier on BOS to ATL, 4,931 flights

These figures cover 399 flights between July 2025 and June 2026. Beyond the headline rate, 8.3% 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

Frontier against every carrier on BOS to ATL

Frontier flew 399 of the 4,931 flights on BOS to ATL, about 8% of it. Its 65.2% on time is 13 points worse than the route as a whole, which runs 78.5%. Ranked by on-time rate it is last of four carriers on the route, where the range runs from Delta at 82.1% to Frontier at 65.2%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 82.1% of the time; JetBlue Airways manages 69.6%. Sample sizes sit next to every figure, because a two-point gap across 850 flights means less than a ten-point one.

On-time performance by carrier on BOS to ATL
Airline	Flights	On time	Avg delay	Cancelled	Grade
Delta Air Lines	3,662	82.1%	75 min	1.77%	B
Spirit Airlinesthin sample	20	70.0%	61 min	0.00%	C+
JetBlue Airways	850	69.6%	63 min	2.35%	C
Frontier Airlines (this page)	399	65.2%	52 min	3.26%	C−

The spread between Delta and JetBlue is 13 points, wide enough that it should decide the booking. On a hundred trips that is 13 more arrivals inside the on-time window.

Departure window

When Frontier 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 399 flights.

5am–8am180 flights62.0%
8am–11am82 flights70.0%
11am–2pm137 flights66.4%
2pm–5pm—
5pm–8pm—
8pm–5am—

Scale runs 55% to 75%. Rows with fewer than 30 flights show a dash.

Book the morning departure. Flights leaving between 8am–11am arrive on time 70.0% of the time, against 62.0% for the early window. That is 8 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 180 flights scheduled in it.

Across the year

Frontier on BOS to ATL through the year

Jul–Sep 202542 flights75.6%
Oct–Dec 202579 flights55.3%
Jan–Mar 202696 flights59.8%
Apr–Jun 2026182 flights69.9%

Scale runs 45% to 80%. Rows with fewer than 30 flights show a dash.

Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 65.2% on time across 399 flights.

Frontier on BOS to ATL did not run the same all year. Its best quarter was Jul–Sep 2025 at 75.6% on time and its weakest Oct–Dec 2025 at 55.3%, a swing of 20 points on roughly 100 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.

Across the week, Friday is the strongest day at 82.1% on time and Sunday the weakest at 47.4%. 35 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Frontier runs late on this route

Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 6,962 reported delay minutes.

Late-arriving aircraft
39%
National Airspace System
35%
Carrier
25%
Extreme weather
1%

39% 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 6,962 reported delay minutes here, that single category outweighs weather by 27 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 6,962 reported delay minutes.

35% 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 2,435 minutes out of 6,962, against a national NAS share of 21%.

Cancellations run at 3.26%, against 1.81% nationally. That is about one flight in 30 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.

Connections and stage length

What a delay here costs

8.3% 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 roughly 50 minutes, which a normal layover absorbs.

The 946 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 66.4% on time across 400 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.

One caution: this is a thin sample. 399 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 Frontier on BOS to ATL

Put together: the delay figures matter less here than the 3.26% cancellation rate. A late arrival costs you roughly 50 minutes; a cancelled flight costs you the day. Book the 8am–11am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 385 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