Today: DL 5631 at 06:45 is the safest bet, 7% chance of being 15+ min late; evening flights run 18–19%.

Safest bet today DL 5631 IND 06:45 → BOS 09:10 · 7% chance 15+ min late · usually 94% on time Riskiest YX 4405 IND 15:30 → BOS 18:18 · 31% chance 15+ min late

Against a calm day 19% average chance a nonstop arrives 15+ min late; 10% for the same flights on a calm-weather day

Every nonstop today

12-month record →

Ranked by the chance of arriving 15+ minutes late, with each flight’s on-time record over Aug 2025 – Jul 2026 beside it. Times are local. Pick a flight for its forecast. Click a column to sort.


DL 5631 Delta flown by Republic Flight history →	IND 06:45	BOS 09:10	7%	2%	0.7%	94%
AA 4716 American flown by Republic Flight history →	IND 09:00	BOS 11:22	11%	3%	0.8%	88%
YX 4408 Republic	IND 09:38	BOS 12:21	13%	4%	0.8%	no record
DL 5647 Delta flown by Republic Flight history →	IND 18:00	BOS 20:34	18%	8%	0.6%	60%
AA 4726 American flown by Republic Flight history →	IND 18:35	BOS 20:59	19%	8%	0.6%	70%
YX 5623 Republic	IND 18:00	BOS 20:26	19%	8%	0.6%	no record
DL 5628 Delta flown by Republic Flight history →	IND 11:00	BOS 13:26	21%	4%	0.8%	91%worse than usual
AA 4368 American flown by Republic Flight history →	IND 14:45	BOS 17:16	30%	11%	1.0%	76%
YX 4405 Republic	IND 15:30	BOS 18:18	31%	14%	1.0%	no record

How these are worked out. Each flight’s odds are our forecast for that day; flights of airlines we don’t forecast yet use their 12-month record and are marked. Makes the connection: the first flight’s 12-month lateness curve, scaled so its chance of arriving 15+ min late matches the day’s forecast, at the layover minus the 45-minute minimum (90 on separate tickets). Arrives on time: first flight not cancelled × connection made × second flight not cancelled × second flight within 15 minutes, each from the day’s forecast.

About this data: forecast odds from our model for Mon, Oct 5 (newest published update); 12-month records from US DOT on-time data, Aug 2025 – Jul 2026, all US airlines; regional flights count under the airline that sells them. JSON