Flight number record

UA 1398

United Airlines · Chicago to Atlanta

Route: ORD → ATL
Departs: 18:20
Flights: 262
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s UA 1398, check with United Airlines.

UA 1398 earns a D+, which is as low as this site's scale goes for a reason. Only 55.6% of flights arrive inside the 15-minute window, 22 points worse than the national rate of 77.6%. Late arrivals average a little over an hour. Treat any tight connection here as a coin flip. That rests on 262 flights, with a median arrival 9 minutes late.

The national on-time rate over the same period is 77.6%, so UA 1398 runs 22 points behind the country as a whole. Across a thousand flights that is about 220 extra late arrivals.

On time

55.6%

Arrivals under 15 minutes late, of 261 completed flights

Avg delay

74 min

Across delayed arrivals only, not all flights

Cancelled

0.38%

National rate is 1.81%

1 hour+ late

16.5%

National rate is 8.1%

These figures cover 262 flights between July 2025 and June 2026. Beyond the headline rate, 16.5% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.

Schedule

When UA 1398 flies

UA 1398 flies ORD to ATL without a single fixed slot. Its most common scheduled departure was 18:20, used on 125 of 262 flights, with 18:35 (37 flights) and 18:10 (37 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 18:20125 flights47.7%
Departs 18:3537 flights14.1%
Departs 18:1037 flights14.1%

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 18:20 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.2%, and UA 1398 runs 13 points worse at 55.6%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.

Against the route

UA 1398 next to ORD to ATL

Every carrier on ORD to ATL combined arrived on time 75.0% of the time across 6,409 flights, so UA 1398 is 19 points behind it. United flew 1,611 flights on the same city pair under all its flight numbers, including this one, and those ran 74.7% on time. Across its whole network United Airlines managed 79.0%, which this flight trails by 23 points.

UA 1398 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
UA 1398thin sample	262	55.6%	74 min	0.38%	D+
All United Airlines on ORD–ATL	1,611	74.7%	68 min	1.12%	C
All carriers on ORD–ATL	6,409	75.0%	81 min	2.26%	B
United Airlines, whole network	821,041	79.0%	72 min	1.01%	B

Across the year

UA 1398 quarter by quarter

UA 1398 did not run the same all year. Its best quarter was Jul–Sep 2025 at 63.9% on time and its weakest Apr–Jun 2026 at 47.5%, a swing of 16 points on roughly 66 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 202561 flights63.9%
Oct–Dec 202573 flights56.2%
Jan–Mar 202687 flights52.9%
Apr–Jun 202641 flights47.5%

Scale runs 40% to 70%. Rows with fewer than 30 flights show a dash.

By weekday, UA 1398 did best on Thursday at 72.2% on time and worst on Friday at 43.6%. Each day rests on about 37 flights, so a gap of 29 points is worth noticing but could still narrow in another year.

Delay causes

Why UA 1398 runs late

One category carries most of the weight here. Late-arriving aircraft accounts for 50% of the 8,549 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
50%
National Airspace System
22%
Carrier
17%
Extreme weather
11%

Extreme weather accounts for 11% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the quarterly figures above are the more useful view of the risk. The national share is 6%, so this operation carries roughly 1.8 times the usual weather exposure. The split is drawn from 8,549 delay minutes reported on UA 1398.

Cancellations are rare at 0.38%, 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

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 16.5% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.

The 606 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 seven other city pairs in the data, including COS to ORD (127), SNA to ORD (66) and IAH to PIT (32), but none flew often enough under UA 1398 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to ORD to ATL only.

One caution: this is a thin sample. 262 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 1398

For a booking, UA 1398 is a flight to put a long connection behind. 16.5% of its completed flights arrived an hour or more late, which a short layover will not absorb. If the onward flight is on a separate ticket, the risk sits with you.

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