Route reliability record

PDX→LAS

Portland to Las Vegas

Flights: 2,983
Period: July 2025 to June 2026
Distance: 763 mi
Carriers: 4

This route lands a B+, 3 points better than the national rate of 77.6%. About one flight in five arrive 15 minutes late or worse, and those flights are late by roughly 55 minutes on average. That is a workable record, not a spotless one. That rests on 2,983 flights, of which Alaska Airlines flew 1,534 at 82.7% on time.

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

On time

80.2%

Arrivals under 15 minutes late, of 2,962 completed flights

Avg delay

54 min

Across delayed arrivals only, not all flights

Cancelled

0.54%

National rate is 1.81%

Best carrier

Alaska

82.7% on time across 1,534 flights

These figures cover 2,983 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 PDX to LAS

The two carriers here are closely matched: 6 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 PDX to LAS
Airline	Flights	On time	Avg delay	Cancelled	Grade
Spirit Airlinesthin sample	128	86.6%	90 min	0.00%	A+
Alaska Airlines	1,534	82.7%	51 min	0.52%	B+
Southwest Airlines	1,149	77.2%	46 min	0.17%	B+
Frontier Airlinesthin sample	172	72.3%	101 min	3.49%	C−

No carrier stands out. Alaska tops the table at 82.7%, 6 points clear of the bottom, which is inside the range this kind of sample moves year to year.

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 24 points, against 6 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am681 flights92.3%
8am–11am607 flights80.5%
11am–2pm310 flights79.1%
2pm–5pm611 flights78.7%
5pm–8pm530 flights68.4%
8pm–5am244 flights75.9%

Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 92.3% of the time, against 68.4% for the evening window. That is 24 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 681 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.January best, December worst

December is the weak month at 73.2% on time, against 85.7% in January. 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. July was the busiest month here, with 303 flights.

Across the week, Tuesday is the strongest day at 86.8% on time and Thursday the weakest at 76.1%. 11 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. Late-arriving aircraft accounts for 43% of the 31,000 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.

Late-arriving aircraft
43%
Carrier
33%
National Airspace System
24%
Extreme weather
0%

43% 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 31,000 reported delay minutes here, that single category outweighs weather by 43 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 31,397 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 92.3% on time here.

Cancellations are rare at 0.54%, 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 4.7% 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 763 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 runs 78.8% on time across 2,984 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.

The sample behind these figures is 2,983 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. January runs 85.7% on time and December 73.2%, a swing of 13 points. If the dates move at all, move them out of December before you think about anything else. 2,962 completed flights over 12 months sit behind that.

Common questions

PDX to LAS questions

How often is PDX to LAS delayed?

About one flight in five arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 19.8% of the 2,983 flights in this analysis, against 22.4% nationally. Delayed flights are late by roughly 55 minutes on average.

Which airline is most reliable on PDX to LAS?

Alaska Airlines leads at 82.7% on time across 1,534 flights. Southwest Airlines is at the other end on 77.2%, a gap of 6 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 PDX to LAS?

The 5am–8am departure window is the strongest at 92.3% on time. The 5pm–8pm window is the weakest at 68.4%, 24 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 December delays on PDX to LAS?

December is the weakest month at 73.2% on time, compared with 85.7% in January. 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. PDX to LAS and LAS to PDX 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