ONT (Ontario) to LAS (Las Vegas) flights arrive on time 79% of the time. The most reliable airline on this route is Southwest Airlines at 80%. The average delay is 77 minutes. Delays on this route are most often caused by the incoming plane arriving late.
Source: Bureau of Transportation Statistics. Updated March 2026.ONT → LAS
ONT (Ontario) to LAS (Las Vegas)
ONT → LAS on-time performance by month
24
25
JanFebMarAprMayJunJulAugSepOctNovDec
Worse
Better
This route is on time most of the time. About 79% of flights arrive on schedule.
Delays on this route are most often caused by the incoming plane arriving late.
Accurate?
Airlines are roughly equal on this route — Southwest Airlines leads slightly at 80% vs Frontier Airlines at 77%.
Airline Comparison
Southwest Airlines leads at 80% on time; Frontier Airlines trails at 77%.
Accurate?
Good to know
Departing from ONT
82% on timeTSA is currently ~5 min. Best time: 4 AM (about 5 min).
Arriving at LAS
77% on timeWhen flights into LAS are late, the average delay is 62 minutes. Build buffer if you have ground plans.
If connecting at LAS: TSA is ~5 min right now. Allow at least 60 minutes for a domestic connection.
Flight cancelled or delayed?
Check what Southwest Airlines owes you — refund rights, action plan, complaint email. Free.
Free flight briefing
Know before you go
Flying ONT → LAS? We'll brief you before takeoff.
Delay riskDOT stats + live data
TSA waitCurrent checkpoint lines
WeatherBoth airports
Gate & terminalLive updates
Know someone flying soon?
Send them the link — delay data, TSA waits, weather, all free.
Data last updated March 2026. Source: Bureau of Transportation Statistics.