Route reliability record

ATL→LAS

Atlanta to Las Vegas

Flights: 4,796
Period: July 2025 to June 2026
Distance: 1,747 mi
Carriers: 4

This route sits in the middle of the pack with a B+. Close to three flights in four arrive on time by the DOT's definition, 2 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 4,796 flights, of which Delta Air Lines flew 3,329 at 77.3% on time.

Delta Air Lines is the most reliable of the three carriers covered here at 77.3% on time across 3,329 flights.

On time

75.9%

Arrivals under 15 minutes late, of 4,751 completed flights

Avg delay

60 min

Across delayed arrivals only, not all flights

Cancelled

0.77%

National rate is 1.81%

Best carrier

Delta

77.3% on time across 3,329 flights

These figures cover 4,796 flights between July 2025 and June 2026. The median arrival is 3 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 ATL to LAS

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 77.3% of the time; Frontier Airlines manages 63.3%. Sample sizes sit next to every figure, because a two-point gap across 562 flights means less than a ten-point one.

On-time performance by carrier on ATL to LAS
Airline	Flights	On time	Avg delay	Cancelled	Grade
Spirit Airlinesthin sample	186	82.2%	68 min	0.54%	B+
Delta Air Lines	3,329	77.3%	55 min	0.60%	B+
Southwest Airlines	719	77.2%	48 min	0.42%	B+
Frontier Airlines	562	63.3%	88 min	2.31%	D

The spread between Delta and Frontier is 14 points, wide enough that it should decide the booking. On a hundred trips that is 14 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 23 points, against 14 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am531 flights90.1%
8am–11am889 flights83.5%
11am–2pm684 flights76.7%
2pm–5pm529 flights76.0%
5pm–8pm1,208 flights70.5%
8pm–5am955 flights66.8%

Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 90.1% of the time, against 66.8% for the overnight window. That is 23 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 1,208 flights scheduled in it.

Across the year

When delays peak on this route

Twelve months, one bar each, drawn from the same 4,796 flights. The strip shows how much of this route's record is set by the calendar rather than by the operation.

Darker means more delays. Figures are on-time percentages.November best, May worst

July is the worst month at 68.9% on time, 12 points below November, the best at 80.6%. 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 427 flights.

Across the week, Wednesday is the strongest day at 82.9% on time and Monday the weakest at 72.7%. 10 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 45% of the 69,000 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
45%
Late-arriving aircraft
30%
National Airspace System
21%
Extreme weather
4%
Security
0%

The largest share of delay minutes, 45%, 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 31,000 of the 69,000 delay minutes reported here. The split is drawn from 68,734 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 90.1% on time here.

Cancellations are rare at 0.77%, 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

7.5% 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 are the about an hour kind, which a normal layover absorbs.

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 85.2% on time across 4,791 flights, 9 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 9 points of difference.

The sample behind these figures is 4,796 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: avoid the 8pm–5am departure. It runs 66.8% on time against 90.1% for the 5am–8am slot, and that 23 points is the largest single thing you control here. Delta Air Lines is the strongest operator if the fares are close. 4,751 completed flights over 12 months sit behind that.

Common questions

ATL to LAS questions

How often is ATL to LAS delayed?

About one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 24.1% of the 4,796 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.

Which airline is most reliable on ATL to LAS?

Delta Air Lines leads at 77.3% on time across 3,329 flights. Frontier Airlines is at the other end on 63.3%, a gap of 14 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 ATL to LAS?

The 5am–8am departure window is the strongest at 90.1% on time. The 8pm–5am window is the weakest at 66.8%, 23 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 ATL to LAS?

July is the weakest month at 68.9% on time, compared with 80.6% in November. Across the year that is 12 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. ATL to LAS and LAS to ATL 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