Flight number record

UA 1734

United Airlines · Boston to Washington

Route: BOS → IAD
Departs: 05:30
Flights: 345
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s UA 1734, check with United Airlines.

UA 1734 earns an A. Nearly every flight arrives inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 19 points better than the national rate of 77.6%. When something does go wrong the average delay runs about an hour. That rests on 345 flights, with a median arrival 13 minutes early.

Set against the rest of the country, UA 1734's record is 19 points better than the US average of 77.6%. That gap is worth roughly 191 fewer late arrivals for every thousand flights.

On time

96.7%

Arrivals under 15 minutes late, of 338 completed flights

Avg delay

56 min

Across delayed arrivals only, not all flights

Cancelled

2.03%

National rate is 1.81%

1 hour+ late

0.6%

National rate is 8.1%

These figures cover 345 flights between July 2025 and June 2026. The median arrival is 13 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 1734 flies

UA 1734 flies BOS to IAD without a single fixed slot. Its most common scheduled departure was 05:30, used on 172 of 345 flights, with 05:45 (134 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 05:30172 flights49.9%
Departs 05:45134 flights38.8%

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 05:30 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and UA 1734 runs 7 points better at 96.7%. 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 1734 next to BOS to IAD

Every carrier on BOS to IAD combined arrived on time 83.0% of the time across 1,464 flights, so UA 1734 is 14 points ahead of it. United flew 1,461 flights on the same city pair under all its flight numbers, including this one, and those ran 83.1% on time. Across its whole network United Airlines managed 79.0%, which this flight beats by 18 points.

UA 1734 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
UA 1734thin sample	345	96.7%	56 min	2.03%	A
All United Airlines on BOS–IAD	1,461	83.1%	76 min	2.05%	B
All carriers on BOS–IAD	1,464	83.0%	76 min	2.05%	B
United Airlines, whole network	821,041	79.0%	72 min	1.01%	B

Across the year

UA 1734 quarter by quarter

Quarter by quarter UA 1734 held fairly steady: 98.9% in Jul–Sep 2025, 95.7% in Oct–Dec 2025, 92.3% in Jan–Mar 2026 and 98.9% in Apr–Jun 2026. A spread of 7 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Jul–Sep 202592 flights98.9%
Oct–Dec 202592 flights95.7%
Jan–Mar 202670 flights92.3%
Apr–Jun 202691 flights98.9%

Scale runs 85% to 100%. Rows with fewer than 30 flights show a dash.

By weekday, UA 1734 ranged from 91.5% on Saturday to 100.0% on Tuesday. With about 49 flights behind each day, a spread of 9 points is inside normal variation, so the day you fly is not worth changing for this flight.

Delay causes

Why UA 1734 runs late

One category carries most of the weight here. Carrier accounts for 72% of the 612 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
72%
National Airspace System
23%
Extreme weather
5%

The largest share of delay minutes, 72%, 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 440 of the 612 delay minutes reported here. The split is drawn from 612 delay minutes reported on UA 1734.

Cancellations sit at 2.03% against a national 1.81%, which is ordinary. Diversions add another 0.00%.

Connections and routes

What a delay on this flight costs

Badly late arrivals are rare here: only 0.6% 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 same number turns up on five other city pairs in the data, including IAD to LAX (171), IAD to PIT (52) and IAD to SEA (30), but none flew often enough under UA 1734 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to BOS to IAD only.

One caution: this is a thin sample. 345 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 1734

For a booking, read UA 1734 as 96.7% on time with 2.03% cancelled over 345 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 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