Flight number record

UA 664

United Airlines · Las Vegas to Chicago

Route: LAS → ORD
Departs: 07:00
Flights: 352
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s UA 664, check with United Airlines.

UA 664 earns an A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 12 points better than the national rate of 77.6%. When something does go wrong the average delay runs close to two hours. That rests on 352 flights, with a median arrival 14 minutes early.

Set against the rest of the country, UA 664's record is 12 points better than the US average of 77.6%. That gap is worth roughly 118 fewer late arrivals for every thousand flights.

On time

89.4%

Arrivals under 15 minutes late, of 349 completed flights

Avg delay

106 min

Across delayed arrivals only, not all flights

Cancelled

0.57%

National rate is 1.81%

1 hour+ late

3.4%

National rate is 8.1%

These figures cover 352 flights between July 2025 and June 2026. The median arrival is 14 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 UA 664 flies

UA 664 flies LAS to ORD without a single fixed slot. Its most common scheduled departure was 07:00, used on 195 of 352 flights, with 07:15 (86 flights) and 07:25 (48 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 07:00195 flights55.4%
Departs 07:1586 flights24.4%
Departs 07:2548 flights13.6%

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 07:00 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and UA 664 runs level with that at 89.4%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.

Against the route

UA 664 next to LAS to ORD

Every carrier on LAS to ORD combined arrived on time 76.5% of the time across 5,297 flights, so UA 664 is 13 points ahead of it. United flew 2,330 flights on the same city pair under all its flight numbers, including this one, and those ran 79.3% on time. Across its whole network United Airlines managed 79.0%, which this flight beats by 10 points.

UA 664 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
UA 664thin sample	352	89.4%	106 min	0.57%	A+
All United Airlines on LAS–ORD	2,330	79.3%	71 min	0.43%	B+
All carriers on LAS–ORD	5,297	76.5%	79 min	1.25%	B
United Airlines, whole network	821,041	79.0%	72 min	1.01%	B

Across the year

UA 664 quarter by quarter

UA 664 did not run the same all year. Its best quarter was Jul–Sep 2025 at 94.5% on time and its weakest Apr–Jun 2026 at 82.9%, a swing of 12 points on roughly 88 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 202592 flights94.5%
Oct–Dec 202590 flights90.0%
Jan–Mar 202688 flights89.5%
Apr–Jun 202682 flights82.9%

Scale runs 75% to 100%. Rows with fewer than 30 flights show a dash.

By weekday, UA 664 did best on Thursday at 100.0% on time and worst on Friday at 82.0%. Each day rests on about 50 flights, so a gap of 18 points is worth noticing but could still narrow in another year.

Delay causes

Why UA 664 runs late

One category carries most of the weight here. Carrier accounts for 51% of the 3,917 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%
National Airspace System
43%
Late-arriving aircraft
5%

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 2,009 of the 3,917 delay minutes reported here. The split is drawn from 3,917 delay minutes reported on UA 664.

Cancellations are rare at 0.57%, 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 routes

What a delay on this flight costs

Badly late arrivals are rare here: only 3.4% 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 1,514 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 same number turns up on eight other city pairs in the data, including ORD to MCI (74), ORD to SRQ (56) and ORD to LGA (53), but none flew often enough under UA 664 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to LAS to ORD only.

One caution: this is a thin sample. 352 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 UA 664

For a booking, UA 664 has one of the better records a US domestic flight can show: 89.4% on time and 0.57% cancelled. That is a base rate, not a promise about any single day.

Where to go next

A flight number here means United 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