United Flight 577 Deals & Information (2026/2027)

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United Flight 577 Route Deals From $147

The cheapest prices found with in the last 7 days for return flights were $293 and $147 for one-way flights to Newark Liberty Intl. Airport for the period specified. Prices and availability are subject to change. Additional terms apply.

Wed, Nov 4 - Tue, Nov 10
STL
Lambert-St. Louis Intl.
EWR
Newark Liberty Intl. Airport
$293 Roundtrip, found 6 hours ago
$293
Roundtrip
found 6 hours ago
Select United flight, departing Wed, Nov 4 from Lambert-St. Louis Intl. to Newark Liberty Intl. Airport, returning Tue, Nov 10, priced at $293 found 6 hours ago
Thu, Nov 5 - Wed, Nov 18
STL
Lambert-St. Louis Intl.
EWR
Newark Liberty Intl. Airport
$302 Roundtrip, found 6 hours ago
$302
Roundtrip
found 6 hours ago
Select United flight, departing Thu, Nov 5 from Lambert-St. Louis Intl. to Newark Liberty Intl. Airport, returning Wed, Nov 18, priced at $302 found 6 hours ago
Wed, Nov 4 - Tue, Nov 10
STL
Lambert-St. Louis Intl.
EWR
Newark Liberty Intl. Airport
$303 Roundtrip, found 6 hours ago
$303
Roundtrip
found 6 hours ago
Select United flight, departing Wed, Nov 4 from Lambert-St. Louis Intl. to Newark Liberty Intl. Airport, returning Tue, Nov 10, priced at $303 found 6 hours ago
Mon, Sep 28 - Thu, Oct 1
STL
Lambert-St. Louis Intl.
EWR
Newark Liberty Intl. Airport
$307 Roundtrip, found 9 hours ago
$307
Roundtrip
found 9 hours ago
Select United flight, departing Mon, Sep 28 from Lambert-St. Louis Intl. to Newark Liberty Intl. Airport, returning Thu, Oct 1, priced at $307 found 9 hours ago
Thu, Nov 5 - Wed, Nov 18
STL
Lambert-St. Louis Intl.
EWR
Newark Liberty Intl. Airport
$312 Roundtrip, found 6 hours ago
$312
Roundtrip
found 6 hours ago
Select United flight, departing Thu, Nov 5 from Lambert-St. Louis Intl. to Newark Liberty Intl. Airport, returning Wed, Nov 18, priced at $312 found 6 hours ago
Fri, Feb 5 - Tue, Feb 9
STL
Lambert-St. Louis Intl.
EWR
Newark Liberty Intl. Airport
$312 Roundtrip, found 17 hours ago
$312
Roundtrip
found 17 hours ago
Select United flight, departing Fri, Feb 5 from Lambert-St. Louis Intl. to Newark Liberty Intl. Airport, returning Tue, Feb 9, priced at $312 found 17 hours 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.