United Airlines operates flight UA1721 between San Diego (SAN) and San Francisco (SFO). This route is typically operated by a 737-800. Based on United Airlines' current Starlink rollout — 525 of 1,787 aircraft equipped (29% of the fleet) — we estimate a 54% probability that this specific flight is equipped with Starlink satellite WiFi.
No aircraft observed on this route. Score reflects the fleet-wide rate for the recorded aircraft type B738: 53.5%.
Equipped
Fleet Size
Coverage
Rollout in progress — confirmed install count pending
Score is based on United Airlines's fleet-wide coverage: 525 of 1787 aircraft are Starlink-equipped (29% fleet ratio). No aircraft-type-specific rollout data is recorded for this route, so the score reflects the fleet-wide average.
This is a moderate-probability route. United Airlines is actively rolling out Starlink — 29% of the fleet is equipped so far — but not every aircraft operating this route is confirmed yet, so coverage on any given departure is not guaranteed.
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Prediction (54%) reflects the chance this specific flight has Starlink. No aircraft observed on this route. Score reflects the fleet-wide rate for the recorded aircraft type B738: 53.5%.
UA1721 is used on more than one route, and the aircraft assigned isn't always the same. The score above reflects the best-equipped version, so your flight may differ.
Aircraft recently seen operating this flight
| Date | Tail Number | Route |
|---|---|---|
| Mar 4, 2026 | N75853 | SFO → KOA |
Check the Starlink probability on other United Airlines routes.
We estimate a 54% probability that flight UA1721 has Starlink WiFi. No aircraft observed on this route. Score reflects the fleet-wide rate for the recorded aircraft type B738: 53.5%. United Airlines is actively rolling out Starlink across its fleet. Check back as our data updates when new aircraft are confirmed.
United Airlines uses Starlink satellite WiFi on equipped aircraft. Flight UA1721 operates SAN to SFO. Our Starlink probability score for this flight is 54%, based on United Airlines' fleet rollout data and confirmed tail numbers.
The most reliable method is to check your specific tail number after check-in — your boarding pass or the United Airlines app may show the aircraft registration. You can then search that tail number on StarlinkFlights.com. Alternatively, our probability score for flight UA1721 is 54% based on current fleet data.
The prediction for UA1721 is based on the aircraft actually observed or claimed to operate this route, not a generic fleet-wide guess. No aircraft observed on this route. Score reflects the fleet-wide rate for the recorded aircraft type B738: 53.5%. A confirmed, dated passenger sighting for this specific flight can override this when one exists.
No prediction can guarantee a specific aircraft. Airlines perform last-minute equipment swaps for maintenance, operational needs, or schedule changes — meaning a Starlink-equipped tail can be replaced by a non-equipped one on the day. A score of 80% or above means historical data strongly favours Starlink on this flight, but it is not a guarantee. For the most reliable information, check the airline's gate display or app on the day of departure.
