Route reliability record

LAS→ATL

Las Vegas to Atlanta

Flights: 4,791
Period: July 2025 to June 2026
Distance: 1,747 mi
Carriers: 4

This route earns a A+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 8 points better than the national rate of 77.6%. When something does go wrong the average delay runs a little over an hour. That rests on 4,791 flights, of which Delta Air Lines flew 3,327 at 87.7% on time.

Delta Air Lines is the most reliable of the three carriers covered here at 87.7% on time across 3,327 flights.

On time

85.2%

Arrivals under 15 minutes late, of 4,733 completed flights

Avg delay

72 min

Across delayed arrivals only, not all flights

Cancelled

0.88%

National rate is 1.81%

Best carrier

Delta

87.7% on time across 3,327 flights

These figures cover 4,791 flights between July 2025 and June 2026. The median arrival is 9 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

Which airline is most reliable on LAS to ATL

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 87.7% of the time; Frontier Airlines manages 74.5%. Sample sizes sit next to every figure, because a two-point gap across 561 flights means less than a ten-point one.

On-time performance by carrier on LAS to ATL
Airline	Flights	On time	Avg delay	Cancelled	Grade
Delta Air Lines	3,327	87.7%	83 min	0.72%	A+
Southwest Airlines	720	82.9%	39 min	0.69%	B+
Spirit Airlinesthin sample	183	82.3%	69 min	0.55%	B+
Frontier Airlines	561	74.5%	70 min	2.14%	C

The spread between Delta and Frontier 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

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 15 points, against 13 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am908 flights92.5%
8am–11am830 flights88.5%
11am–2pm947 flights81.0%
2pm–5pm496 flights84.0%
5pm–8pm41 flights78.0%
8pm–5am1,569 flights82.4%

Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 92.5% of the time, against 78.0% for the evening window. That is 15 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8pm–5am window is the busiest, with 1,569 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 13 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.February best, July worst

July is the worst month at 76.9% on time, 13 points below February, the best at 89.4%. 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. December was the busiest month here, with 429 flights.

Across the week, Wednesday is the strongest day at 91.6% on time and Friday the weakest at 82.3%. 9 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. Carrier accounts for 51% of the 51,000 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.

Carrier
51%
Late-arriving aircraft
33%
National Airspace System
15%
Extreme weather
1%
Security
0%

The largest share of delay minutes, 51%, 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 26,000 of the 51,000 delay minutes reported here. The split is drawn from 50,548 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 92.5% on time here.

Cancellations are rare at 0.88%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.

Connections and stage length

What a delay here actually costs

Badly late arrivals are rare here: only 4.8% 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.

At 1,747 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 is a different operation and performs like one: it runs 75.9% on time across 4,796 flights, 9 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 9 points of difference.

The sample behind these figures is 4,791 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. February runs 89.4% on time and July 76.9%, a swing of 13 points. If the dates move at all, move them out of July before you think about anything else. 4,733 completed flights over 12 months sit behind that.

Common questions

LAS to ATL questions

How often is LAS to ATL delayed?

About one flight in seven arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 14.8% of the 4,791 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 LAS to ATL?

Delta Air Lines leads at 87.7% on time across 3,327 flights. Frontier Airlines is at the other end on 74.5%, a gap of 13 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 LAS to ATL?

The 5am–8am departure window is the strongest at 92.5% on time. The 5pm–8pm window is the weakest at 78.0%, 15 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 July delays on LAS to ATL?

July is the weakest month at 76.9% on time, compared with 89.4% in February. Across the year that is 13 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. LAS to ATL and ATL to LAS 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