Flight number record

AS 551

Alaska Airlines · Seattle to Las Vegas

Route: SEA → LAS
Departs: 16:50
Flights: 260
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s AS 551, check with Alaska Airlines.

AS 551 lands a B, 3 points better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about 50 minutes on average. That is a workable record, not a spotless one. That rests on 260 flights, with a median arrival 6 minutes early.

On time

80.5%

Arrivals under 15 minutes late, of 257 completed flights

Avg delay

49 min

Across delayed arrivals only, not all flights

Cancelled

1.15%

National rate is 1.81%

1 hour+ late

5.4%

National rate is 8.1%

These figures cover 260 flights between July 2025 and June 2026. The median arrival is 6 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.

Schedule

When AS 551 flies

AS 551 flies SEA to LAS without a single fixed slot. Its most common scheduled departure was 16:50, used on 38 of 260 flights, with 16:43 (36 flights) and 17:01 (30 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 16:5038 flights14.6%
Departs 16:4336 flights13.8%
Departs 17:0130 flights11.5%

Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.

Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.

A 16:50 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 72.4%, and AS 551 runs 8 points better at 80.5%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.

Against the route

AS 551 next to SEA to LAS

Every carrier on SEA to LAS combined arrived on time 77.7% of the time across 5,650 flights, so AS 551 is 3 points ahead of it. Alaska flew 2,638 flights on the same city pair under all its flight numbers, including this one, and those ran 78.0% on time. Across its whole network Alaska Airlines managed 79.1%, close to this flight's figure.

AS 551 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
AS 551thin sample	260	80.5%	49 min	1.15%	B
All Alaska Airlines on SEA–LAS	2,638	78.0%	47 min	0.91%	B+
All carriers on SEA–LAS	5,650	77.7%	54 min	0.83%	B+
Alaska Airlines, whole network	293,372	79.1%	52 min	1.28%	B

Across the year

AS 551 quarter by quarter

AS 551 did not run the same all year. Its best quarter was Apr–Jun 2026 at 90.9% on time and its weakest Jul–Sep 2025 at 73.2%, a swing of 18 points on roughly 65 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.

Jul–Sep 202541 flights73.2%
Oct–Dec 202577 flights78.7%
Jan–Mar 202676 flights77.3%
Apr–Jun 202666 flights90.9%

Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.

By weekday, AS 551 did best on Wednesday at 89.7% on time and worst on Friday at 70.3%. Each day rests on about 37 flights, so a gap of 19 points is worth noticing but could still narrow in another year.

Delay causes

Why AS 551 runs late

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 2,465 reported delay minutes.

Carrier
37%
National Airspace System
34%
Late-arriving aircraft
29%
Extreme weather
1%

The largest share of delay minutes, 37%, 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 904 of the 2,465 delay minutes reported here. The split is drawn from 2,465 delay minutes reported on AS 551.

Cancellations sit at 1.15% against a national 1.81%, which is ordinary. Diversions add another 0.00%.

Connections and routes

What a delay on this flight costs

5.4% 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 50 minutes, which a normal layover absorbs.

The 867 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 same number turns up on one other city pair in the data, including DFW to SAN (21), but none flew often enough under AS 551 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to SEA to LAS only.

One caution: this is a thin sample. 260 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 AS 551

For a booking, read AS 551 as 80.5% on time with 1.15% cancelled over 260 flights. Those are rates from the past twelve months, not a forecast for any particular day.

Where to go next

A flight number here means Alaska Airlines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.

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