Skip to content
WanderNerd
Check a flight

Flight Reliability

UA 1721 · United Airlines

San Francisco → Kailua-Kona (SFO–KOA)96% of its flights flew this route. The rest (SAN–SFO) are included in these numbers.

95
Nerd Approved
WanderNerd Reliability Score
90%
Arrive within 15 minutes
6 min early
Average arrival delay
0.3%
Cancelled
12 min early
Median arrival delay

Based on 380 historical flights. Data through May 2026.

What the data says

The 6–9 AM departure wins.

UA 1721 departing between 6–9 AM arrived on time 99% of the time, versus 87% between 9 AM–12 PM.

Friday is doing you no favors.

UA 1721 arrived on time 95% of the time on Sundays. On Fridays: 86%.

Better than the United Airlines network average.

UA 1721 arrived on time 90% of the time, versus 79% across the United Airlines network.

It basically never cancels.

Out of 380 scheduled flights, only 0.3% were cancelled.

The breakdown

On-time by weekday
  • Mon91%(55 flights)
  • Tue87%(52 flights)
  • Wed87%(52 flights)
  • Thu93%(53 flights)
  • Fri86%(55 flights)
  • Sat91%(54 flights)
  • Sun95%(56 flights)
On-time by departure window
  • 6–9 AM99%(79 flights)
  • 9 AM–12 PM87%(298 flights)
On-time trend by month
97%
May

Jun 100% → May 97% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 2025100%30
July 202584%31
August 202577%31
September 202587%30
October 202583%30
November 202590%30
December 202584%31
January 202697%31
February 202693%41
March 202684%32
April 2026100%29
May 202697%31
Departures on time
87%
Diverted
0.5%
Flights flown
377
Months covered
12

Same route, other flights

Keep nerding

Based on 380 historical flights, because apparently we checked. Historical flight data: U.S. Bureau of Transportation Statistics, June 2025 – May 2026. Data through May 2026. How we calculate this.