Carrier route record

F9BOS→RDU

Frontier Airlines · Boston to Raleigh

Flights: 159
Period: July 2025 to June 2026
Share of route: 6%
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 RDU sits in the middle of the pack with a C+. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.6%. The late ones land about 50 minutes behind schedule. That rests on 159 flights. The strongest carrier on the route with a full sample, Delta Air Lines, flew 1,437 at 77.6% on time.

The US average over the same twelve months is 77.6%, so there is little to separate Frontier on BOS to RDU from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

On time

74.7%

Arrivals under 15 minutes late, of 158 completed flights

Avg delay

49 min

Across delayed arrivals only, not all flights

Cancelled

0.00%

National rate is 1.81%

Whole route

76.3%

Every carrier on BOS to RDU, 2,816 flights

These figures cover 159 flights between July 2025 and June 2026. The median arrival is 4 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.

Carrier by carrier

Frontier against every carrier on BOS to RDU

Frontier flew 159 of the 2,816 flights on BOS to RDU, about 6% of it. Its 74.7% on time is 2 points worse than the route as a whole, which runs 76.3%. Ranked by on-time rate it is number three of four carriers on the route, where the range runs from Republic at 82.4% to JetBlue at 74.0%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The two carriers here are closely matched: 4 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 RDU
Airline	Flights	On time	Avg delay	Cancelled	Grade
Republic Airwaysthin sample	136	82.4%	75 min	3.68%	B−
Delta Air Lines	1,437	77.6%	86 min	2.44%	B
Frontier Airlines (this page)thin sample	159	74.7%	49 min	0.00%	C+
JetBlue Airways	1,084	74.0%	68 min	2.58%	C

No carrier stands out. Delta tops the table at 77.6%, 4 points clear of the bottom, which is inside the range this kind of sample moves year to year.

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 12 points, against 4 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am—
8am–11am111 flights78.4%
11am–2pm48 flights66.0%
2pm–5pm—
5pm–8pm—
8pm–5am—

Scale runs 60% to 85%. Rows with fewer than 30 flights show a dash.

The weak window here is the middle of the day, not the evening: 11am–2pm runs 66.0% on time against 78.4% for 8am–11am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 8am–11am window is the busiest, with 111 flights scheduled in it.

Across the year

Frontier on BOS to RDU through the year

Jul–Sep 202538 flights81.6%
Oct–Dec 202541 flights78.0%
Jan–Mar 202628 flights—
Apr–Jun 202652 flights74.5%

Scale runs 65% to 85%. 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 74.7% on time across 159 flights.

Quarter by quarter Frontier on BOS to RDU held fairly steady: 81.6% in Jul–Sep 2025, 78.0% in Oct–Dec 2025 and 74.5% in Apr–Jun 2026. A spread of 7 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Across the week, Friday is the strongest day at 83.9% on time and Thursday the weakest at 71.0%. 13 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Frontier runs late on this route

One category carries most of the weight here. Carrier accounts for 44% of the 1,958 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.

Carrier
44%
Late-arriving aircraft
34%
National Airspace System
22%

34% 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 1,958 reported delay minutes here, that single category outweighs weather by 34 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 1,958 reported delay minutes.

The largest share of delay minutes, 44%, 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 860 of the 1,958 delay minutes reported here.

Cancellations are rare at 0.00%, below the national 1.81% and low enough to earn the plus on the grade. Almost no flights are called off; the risk here is arriving late, not not arriving.

Connections and stage length

What a delay here costs

Badly late arrivals are rare here: only 4.4% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.

The 612 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 80.5% on time across 159 flights, 6 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 6 points of difference.

One caution: this is a thin sample. 159 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 RDU

Put together: treat all of this as provisional. 159 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 74.7% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 158 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