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.

Sat, Oct 17 - Sat, Oct 24
STL
Lambert-St. Louis Intl.
EWR
Newark Liberty Intl. Airport
$293 Roundtrip, found 9 hours ago
$293
Roundtrip
found 9 hours ago
Select United flight, departing Sat, Oct 17 from Lambert-St. Louis Intl. to Newark Liberty Intl. Airport, returning Sat, Oct 24, priced at $293 found 9 hours ago
Tue, Dec 1 - Sat, Dec 5
STL
Lambert-St. Louis Intl.
EWR
Newark Liberty Intl. Airport
$299 Roundtrip, found 3 days ago
$299
Roundtrip
found 3 days ago
Select United flight, departing Tue, Dec 1 from Lambert-St. Louis Intl. to Newark Liberty Intl. Airport, returning Sat, Dec 5, priced at $299 found 3 days ago
Tue, Dec 22 - Fri, Dec 25
STL
Lambert-St. Louis Intl.
EWR
Newark Liberty Intl. Airport
$301 Roundtrip, found 4 days ago
$301
Roundtrip
found 4 days ago
Select United flight, departing Tue, Dec 22 from Lambert-St. Louis Intl. to Newark Liberty Intl. Airport, returning Fri, Dec 25, priced at $301 found 4 days ago
Sat, Oct 17 - Sat, Oct 24
STL
Lambert-St. Louis Intl.
EWR
Newark Liberty Intl. Airport
$303 Roundtrip, found 9 hours ago
$303
Roundtrip
found 9 hours ago
Select United flight, departing Sat, Oct 17 from Lambert-St. Louis Intl. to Newark Liberty Intl. Airport, returning Sat, Oct 24, priced at $303 found 9 hours ago
Sat, Oct 24 - Thu, Oct 29
STL
Lambert-St. Louis Intl.
EWR
Newark Liberty Intl. Airport
$305 Roundtrip, found 2 days ago
$305
Roundtrip
found 2 days ago
Select United flight, departing Sat, Oct 24 from Lambert-St. Louis Intl. to Newark Liberty Intl. Airport, returning Thu, Oct 29, priced at $305 found 2 days ago
Sat, Oct 24 - Thu, Oct 29
STL
Lambert-St. Louis Intl.
EWR
Newark Liberty Intl. Airport
$306 Roundtrip, found 2 days ago
$306
Roundtrip
found 2 days ago
Select United flight, departing Sat, Oct 24 from Lambert-St. Louis Intl. to Newark Liberty Intl. Airport, returning Thu, Oct 29, priced at $306 found 2 days ago
Sat, Oct 17 - Sat, Oct 24
STL
Lambert-St. Louis Intl.
EWR
Newark Liberty Intl. Airport
$315 Roundtrip, found 9 hours ago
$315
Roundtrip
found 9 hours ago
Select United flight, departing Sat, Oct 17 from Lambert-St. Louis Intl. to Newark Liberty Intl. Airport, returning Sat, Oct 24, priced at $315 found 9 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.