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.

FRONTIER · FLIGHT F9 2146 IN THE AIR (OFF 12:25 AM PT, ETA 5:31 AM CT) · SCHEDULED TIME UNKNOWN
Today

F9 2146 · LAS → ORD

took off 12:25 AM PT · expected to land 5:31 AM CT (scheduled time unknown)
Forecast issued Tue 3:00 AM ET · 1h before departure

Odds over time

Arrive at ORD more than 15 minutes late?
30% chance · ±3 pts – · 24h
HOW SURE WE ARE Very high. The odds now come almost entirely from live conditions.
LIVE IN THE AIR 0% 20% 40% 60% 80% 3h Now Departs Lands