Flight number record
YX 5619
Republic Airways · Boston to Milwaukee
- Route
- BOS → MKE
- Departs
- 20:45
- Flights
- 290
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s YX 5619, check with Republic Airways. Republic Airways flies under contract for larger airlines, so a ticket for this flight may show a different airline code and number.
YX 5619 sits in the middle of the pack with a B−. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 290 flights, with a median arrival 6 minutes early.
Key figures
On time
75.0%
Arrivals under 15 minutes late, of 272 completed flights
Avg delay
61 min
Across delayed arrivals only, not all flights
Cancelled
5.86%
National rate is 1.81%
1 hour+ late
9.9%
National rate is 8.1%
These figures cover 290 flights between July 2025 and June 2026. Beyond the headline rate, 9.9% 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 YX 5619 flies
YX 5619 flies BOS to MKE without a single fixed slot. Its most common scheduled departure was 20:45, used on 49 of 290 flights, with 17:20 (43 flights) and 16:50 (31 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 20:4549 flights16.9%
- Departs 17:2043 flights14.8%
- Departs 16:5031 flights10.7%
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 20:45 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.5%, and YX 5619 runs 5 points better at 75.0%. 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
YX 5619 next to BOS to MKE
Every carrier on BOS to MKE combined arrived on time 80.5% of the time across 742 flights, so YX 5619 is 6 points behind it. Republic flew 549 flights on the same city pair under all its flight numbers, including this one, and those ran 80.8% on time. Across its whole network Republic Airways managed 78.5%, which this flight trails by 4 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| YX 5619thin sample | 290 | 75.0% | 61 min | 5.86% | B− |
| All Republic Airways on BOS–MKE | 549 | 80.8% | 59 min | 4.01% | B− |
| All carriers on BOS–MKE | 742 | 80.5% | 63 min | 3.23% | B− |
| Republic Airways, whole network | 361,482 | 78.5% | 72 min | 4.08% | B− |
Across the year
YX 5619 quarter by quarter
YX 5619 did not run the same all year. Its best quarter was Jan–Mar 2026 at 85.5% on time and its weakest Jul–Sep 2025 at 59.5%, a swing of 26 points on roughly 73 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 202577 flights59.5%
- Oct–Dec 202552 flights69.6%
- Jan–Mar 202683 flights85.5%
- Apr–Jun 202678 flights82.9%
Scale runs 50% to 90%. Rows with fewer than 30 flights show a dash.
By weekday, YX 5619 did best on Wednesday at 84.4% on time and worst on Friday at 68.2%. Each day rests on about 41 flights, so a gap of 16 points is worth noticing but could still narrow in another year.
Delay causes
Why YX 5619 runs late
One category carries most of the weight here. Late-arriving aircraft accounts for 50% of the 4,151 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.
- 50%Late-arriving aircraft
- 26%National Airspace System
- 23%Carrier
- 0%Extreme weather
50% 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 4,151 reported delay minutes here, that single category outweighs weather by 50 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 4,151 delay minutes reported on YX 5619.
Cancellations run at 5.86%, against 1.81% nationally. That is roughly one flight in fifteen cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.
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. 9.9% 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 860 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 five other city pairs in the data, including MKE to BOS (227), GSO to LGA (13) and JFK to IND (11), but none flew often enough under YX 5619 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to BOS to MKE only.
One caution: this is a thin sample. 290 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 YX 5619
For a booking, the cancellation rate is the figure to plan around on YX 5619: 5.86% of its 290 scheduled flights did not operate. A late arrival costs about an hour, but a cancellation costs the day, so leave a later option open.
Related
Where to go next
- BOS to MKE, every carrier and departure
- MKE to BOS, the return direction
- Republic Airways 5614 on the same route87.4%
- Boston Logan International (BOS) delay statistics
- Republic Airways on-time record
- Every Republic Airways flight number with a record
- The most and least reliable flight numbers in the US
- Why the first flight of the morning is statistically safest
A flight number here means Republic Airways’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.