Carrier route record

F9ATL→BOS

Frontier Airlines · Atlanta to Boston

Flights: 453
Period: September 2025 to August 2026
Share of route: 9%
Carriers: 4

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

Frontier on ATL to BOS draws a C. About one flight in three arrives at least 15 minutes late, and the typical late arrival is about 55 minutes behind schedule. Build slack into anything you connect to. That rests on 453 flights. The strongest carrier on the route with a full sample, Delta Air Lines, flew 3,731 at 74.4% on time.

The national on-time rate over the same period is 77.3%, so Frontier on ATL to BOS runs 10 points behind the country as a whole. Across a thousand flights that is about 100 extra late arrivals.

On time

67.3%

Arrivals under 15 minutes late, of 440 completed flights

Avg delay

54 min

Across delayed arrivals only, not all flights

Cancelled

2.87%

National rate is 1.89%

Whole route

72.8%

Every carrier on ATL to BOS, 5,054 flights

These figures cover 453 flights between September 2025 and August 2026. Beyond the headline rate, 9.8% of arrivals land a full hour or more behind schedule, against 8.3% nationally.

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Carrier by carrier

Frontier against every carrier on ATL to BOS

Frontier flew 453 of the 5,054 flights on ATL to BOS, about 9% of it. Its 67.3% on time is 6 points worse than the route as a whole, which runs 72.8%. Ranked by on-time rate it is number three of four carriers on the route, where the range runs from Delta at 74.4% to Spirit at 61.5%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.

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 ATL to BOS
Airline	Flights	On time	Avg delay	Cancelled	Grade
Delta Air Lines	3,731	74.4%	61 min	1.82%	C
JetBlue Airways	857	69.2%	92 min	4.08%	C−
Frontier Airlines (this page)	453	67.3%	54 min	2.87%	C
Spirit Airlinesthin sample	13	61.5%	57 min	0.00%	D+

JetBlue Airways cancels 4.1% 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.

Flight by flight

Frontier flight numbers on ATL to BOS

F9 351205:0573.1% · 255 flights

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Departure window

When Frontier runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 19 points, against 5 points between the best and worst carrier.

5am–8am169 flights76.4%
8am–11am98 flights69.8%
11am–2pm—
2pm–5pm—
5pm–8pm—
8pm–5am186 flights57.5%

Scale runs 50% to 80%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 57.5% on time, against 76.4% 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 186 flights scheduled in it.

Across the year

Frontier on ATL to BOS through the year

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

January is the weak month at 47.1% on time, against 75.7% in August. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. May was the busiest month here, with 62 flights.

Across the week, Friday is the strongest day at 72.5% on time and Sunday the weakest at 58.5%, a spread of 14 points.

Arrival by arrival

How late Frontier on ATL to BOS runs when it is late

Frontier on ATL to BOS often beats the schedule: 116 of 440 completed flights, 26%, arrived 15 minutes or more early. The 144 late arrivals split 50 under half an hour, 51 between 30 and 60 minutes, and 43 an hour or more.

15+ min early116 flights26.4%
Within 15 min180 flights40.9%
15–29 min late50 flights11.4%
30–59 min late51 flights11.6%
1–2 hours late30 flights6.8%
2+ hours late13 flights3.0%

Scale runs 0% to 100%.

Share of 440 completed flights by arrival against schedule.

34 of 156 late departures made up the time and arrived on time, 22% of them. In the other direction, 22 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at BOS.

The worst days

Worst days for Frontier on ATL to BOS

The latest arrival of the period was on 4 January 2026, 4 hours 16 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. On three of the five worst days the largest share was filed as carrier-caused (crew, maintenance, fuelling, baggage).

The latest arrivals of Frontier on ATL to BOS in the period
Date	Arrived late by	Largest filed cause
4 January 2026	4 hours 16 minutes	Late-arriving aircraft
4 January 2026	3 hours 38 minutes	Carrier
25 August 2026	3 hours 32 minutes	Carrier
7 June 2026	3 hours 27 minutes	Carrier
12 April 2026	3 hours 5 minutes	Late-arriving aircraft

Delay causes

Why Frontier runs late on this route

Carrier accounts for 45% of the 7,823 delay minutes carriers reported here, and the remaining four split what is left.

Carrier
45%
Late-arriving aircraft
45%
National Airspace System
10%

45% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 7,823 reported delay minutes here, that single category outweighs weather by 45 to one. The split is drawn from 7,823 reported delay minutes.

The largest share of delay minutes, 45%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 3,517 of the 7,823 delay minutes reported here.

Cancellations run at 2.87%, against 1.89% nationally. That is roughly 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

9.8% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.

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.

The return leg is a different operation and performs like one: it runs 62.6% on time across 453 flights, 5 points below 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 5 points of difference.

One caution: this is a thin sample. 453 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 ATL to BOS

Put together: the delay figures matter less here than the 2.87% cancellation rate. A late arrival costs you about 55 minutes; a cancelled flight costs you the day. Book the 5am–8am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 440 completed flights over 12 months sit behind that.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures