Tracked live by the FAA, but its flight plan was first seen after takeoff, so we don't know the scheduled time and can't say whether it's late.

CAPE AIR · FLIGHT 9K 519 SCHEDULED · SCHEDULED TIME UNKNOWN
Today

9K 519 · BOS → ACK

departs 5:42 PM ET · arrives 6:21 PM ET
Your aircraft is N2611X (C402), coming in as 9K 5341 from ACK: still at ACK, due off about 3:32 PM ET, 88 min before departure.
Forecast issued Thu 1:00 PM ET · 5h before departure

Odds over time

Arrive at ACK more than 15 minutes late?
34% chance · ±0 pts – · 24h
HOW SURE WE ARE High. The odds now come mostly from live FAA and airport data.
WEATHER FORECASTS LIVE IN THE AIR 0% 20% 40% 60% 80% 22h 12h 6h Now Departs Lands