Carrier route record
YXBOS→MKE
Republic Airways · Boston to Milwaukee
- Flights
- 540
- Period
- September 2025 to August 2026
- Share of route
- 73%
- Carriers
- 3
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Republic Airways.
Republic on BOS to MKE lands a B−, 5 points better than the national rate of 77.3%. About one flight in six arrives 15 minutes late or worse, and those flights are late by about 55 minutes on average. That rests on 540 flights, with a median arrival 9 minutes early.
Set against the rest of the country, Republic's BOS to MKE record is 5 points better than the US average of 77.3%. That gap is worth roughly 49 fewer late arrivals for every thousand flights.
Key figures
On time
82.2%
Arrivals under 15 minutes late, of 516 completed flights
Avg delay
54 min
Across delayed arrivals only, not all flights
Cancelled
4.26%
National rate is 1.89%
Whole route
82.7%
Every carrier on BOS to MKE, 737 flights
These figures cover 540 flights between September 2025 and August 2026. The median arrival is 9 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.
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Carrier by carrier
Republic against every carrier on BOS to MKE
Republic flew 540 of the 737 flights on BOS to MKE, most of the route. Its 82.2% on time is about level with the route as a whole at 82.7%. Ranked by on-time rate it is number two of three carriers on the route, where the range runs from JetBlue at 87.6% to Delta at 58.3%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| JetBlue Airwaysthin sample | 172 | 87.6% | 58 min | 1.16% | A |
| Republic Airways (this page) | 540 | 82.2% | 54 min | 4.26% | B− |
| Delta Air Linesthin sample | 25 | 58.3% | 92 min | 4.00% | D− |
Flight by flight
Republic flight numbers on BOS to MKE
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Departure window
When Republic runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 24 points, against half a point between the best and worst carrier.
- 5am–8am—
- 8am–11am234 flights88.6%
- 11am–2pm17 flights—
- 2pm–5pm161 flights79.2%
- 5pm–8pm78 flights64.5%
- 8pm–5am50 flights88.9%
Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 64.5% on time, against 88.9% for the 8pm–5am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 8am–11am window is the busiest, with 234 flights scheduled in it.
Across the year
Republic on BOS to MKE through the year
Delays peak in September, when the on-time rate falls to 61.8%. June is the strongest month at 95.7%. Moving a flexible trip across that boundary buys 34 points. October was the busiest month here, with 57 flights.
Across the week, Saturday is the strongest day at 90.2% on time and Tuesday the weakest at 77.1%, a spread of 13 points.
Arrival by arrival
How late Republic on BOS to MKE runs when it is late
Republic on BOS to MKE often beats the schedule: 177 of 516 completed flights, 34%, arrived 15 minutes or more early. The 92 late arrivals split 30 under half an hour, 32 between 30 and 60 minutes, and 30 an hour or more.
- 15+ min early177 flights34.3%
- Within 15 min247 flights47.9%
- 15–29 min late30 flights5.8%
- 30–59 min late32 flights6.2%
- 1–2 hours late24 flights4.7%
- 2+ hours late6 flights1.2%
Scale runs 0% to 100%.
Share of 516 completed flights by arrival against schedule.
21 of 101 late departures made up the time and arrived on time, 21% of them. 12 flights left on time and still arrived late.
The worst days
Worst days for Republic on BOS to MKE
The latest arrival of the period was on 11 March 2026, 3 hours 30 minutes behind schedule; most of its delay minutes were filed as national airspace system delay. The five worst days are spread across March, July, May, September and April, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 11 March 2026 | 3 hours 30 minutes | National Airspace System |
| 6 July 2026 | 3 hours 18 minutes | Late-arriving aircraft |
| 19 May 2026 | 3 hours 6 minutes | National Airspace System |
| 12 September 2025 | 2 hours 36 minutes | Carrier |
| 10 April 2026 | 2 hours 6 minutes | Carrier |
Delay causes
Why Republic runs late on this route
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 4,977 reported delay minutes.
- 40%Late-arriving aircraft
- 34%Carrier
- 24%National Airspace System
- 2%Extreme weather
40% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 4,977 reported delay minutes here, that single category outweighs weather by 25 to one. The split is drawn from 4,977 reported delay minutes.
The largest share of delay minutes, 34%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 1,704 of the 4,977 delay minutes reported here.
Cancellations run at 4.26%, against 1.89% nationally. That is about one flight in 25 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 stage length
What a delay here costs
5.8% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about 55 minutes, which a normal layover absorbs.
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.
The return leg is a different operation and performs like one: it runs 72.7% on time across 540 flights, 10 points below this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 10 points of difference.
One caution: this is a thin sample. 540 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 Republic on BOS to MKE
Put together: the delay figures matter less here than the 4.26% cancellation rate. A late arrival costs you about 55 minutes; a cancelled flight costs you the day. Book the 8pm–5am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 516 completed flights over 12 months sit behind that.
Related
Where to go next
- BOS to MKE, every carrier
- Republic on MKE to BOS, the return leg
- JetBlue Airways on BOS to MKE87.6%
- Republic Airways network-wide record
- Boston Logan International (BOS) delay statistics
- Milwaukee Mitchell International (MKE) delay statistics
- The US routes with the most cancellations
- Why the first flight of the morning is statistically safest
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.