United Flight 577 Deals & Information (2026/2027)

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United Flight 577 Route Deals From $150

The cheapest prices found with in the last 7 days for return flights were $297 and $150 for one-way flights to Newark Liberty Intl. Airport for the period specified. Prices and availability are subject to change. Additional terms apply.

Thu, Sep 24 - Wed, Sep 30
STL
Lambert-St. Louis Intl.
EWR
Newark Liberty Intl. Airport
$297 Roundtrip, found 6 days ago
$297
Roundtrip
found 6 days ago
Select United flight, departing Thu, Sep 24 from Lambert-St. Louis Intl. to Newark Liberty Intl. Airport, returning Wed, Sep 30, priced at $297 found 6 days ago
Mon, Oct 26 - Wed, Nov 4
STL
Lambert-St. Louis Intl.
EWR
Newark Liberty Intl. Airport
$304 Roundtrip, found 6 days ago
$304
Roundtrip
found 6 days ago
Select United flight, departing Mon, Oct 26 from Lambert-St. Louis Intl. to Newark Liberty Intl. Airport, returning Wed, Nov 4, priced at $304 found 6 days ago
Thu, Sep 24 - Wed, Sep 30
STL
Lambert-St. Louis Intl.
EWR
Newark Liberty Intl. Airport
$307 Roundtrip, found 6 days ago
$307
Roundtrip
found 6 days ago
Select United flight, departing Thu, Sep 24 from Lambert-St. Louis Intl. to Newark Liberty Intl. Airport, returning Wed, Sep 30, priced at $307 found 6 days ago

Frequently asked questions

What route does flight number UA577 take?
UA577 travels from DEN to GEG directly. This service generally takes 2 hours and 24 minutes.
How often is UA577 on time?
Roughly 90% of UA577 flights arrive according to scheduled times — so if you're jetting from Denver, CO Airport (DEN-Denver Intl.) to GEG, you can be confident that you'll touch down at your destination ASAP. In the rare event that your United Airlines trip is delayed, you can expect to wait about 8 minutes. Because of the air carrier's top-notch service, this route has a star rating of 4.6.
What kind of plane is on flight number UA577?
The Boeing 737-800 is the kind of plane that's mostly used for flight number UA577. This flight almost always sets off from DEN and comes in to land at GEG.
If I am not able to travel due to COVID-19, can I change my flight to a later date?
For more info about changing your UA577 flight with Travelocity, please visit our Customer Service Portal.