Carrier route record

DLBOS→LAS

Delta Air Lines · Boston to Las Vegas

Flights: 593
Period: July 2025 to June 2026
Share of route: 36%
Carriers: 2

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

Delta on BOS to LAS lands a B, level with the national rate of 77.6%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 593 flights, with a median arrival 5 minutes early.

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

On time

77.9%

Arrivals under 15 minutes late, of 583 completed flights

Avg delay

58 min

Across delayed arrivals only, not all flights

Cancelled

1.35%

National rate is 1.81%

Whole route

75.6%

Every carrier on BOS to LAS, 1,638 flights

These figures cover 593 flights between July 2025 and June 2026. The median arrival is 5 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

Delta against every carrier on BOS to LAS

Delta flew 593 of the 1,638 flights on BOS to LAS, about 36% of it. Its 77.9% on time is 2 points better than the route as a whole, which runs 75.6%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from Delta at 77.9% to JetBlue at 74.3%.

Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.

On-time performance by carrier on BOS to LAS
Airline	Flights	On time	Avg delay	Cancelled	Grade
Delta Air Lines (this page)	593	77.9%	58 min	1.35%	B
JetBlue Airways	1,045	74.3%	69 min	1.15%	C

Flight by flight

Delta flight numbers on BOS to LAS

DL 49707:4081.4% · 359 flights

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

5am–8am199 flights86.4%
8am–11am166 flights75.3%
11am–2pm4 flights—
2pm–5pm—
5pm–8pm208 flights74.0%
8pm–5am16 flights—

Scale runs 65% to 90%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 86.4% of the time, against 74.0% for the evening window. That is 12 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5pm–8pm window is the busiest, with 208 flights scheduled in it.

Across the year

Delta on BOS to LAS through the year

Darker means more delays. Figures are on-time percentages.April best, February worst

February is the weak month at 68.1% on time, against 86.7% in April. 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. March was the busiest month here, with 61 flights.

Across the week, Saturday is the strongest day at 85.5% on time and Tuesday the weakest at 72.2%. 13 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Delta 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 7,512 reported delay minutes.

Carrier
40%
Late-arriving aircraft
32%
National Airspace System
26%
Extreme weather
2%

The largest share of delay minutes, 40%, 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 2,987 of the 7,512 delay minutes reported here. The split is drawn from 7,512 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 86.4% on time here.

Cancellations sit at 1.35% against a national 1.81%, which is ordinary. Diversions add another 0.34%.

Connections and stage length

What a delay here costs

6.3% 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 about an hour, which a normal layover absorbs.

At 2,381 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.

The return leg runs 76.5% on time across 593 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. 593 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 BOS to LAS

Put together: treat all of this as provisional. 593 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 77.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 583 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