United Flight 577 Deals & Information (2026/2027)

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United Flight 577 Route Deals From $139

The cheapest prices found with in the last 7 days for return flights were $287 and $139 for one-way flights to Newark Liberty Intl. Airport for the period specified. Prices and availability are subject to change. Additional terms apply.

Tue, Dec 1 - Sat, Dec 5
STL
Lambert-St. Louis Intl.
EWR
Newark Liberty Intl. Airport
$287 Roundtrip, found 10 hours ago
$287
Roundtrip
found 10 hours ago
Select United flight, departing Tue, Dec 1 from Lambert-St. Louis Intl. to Newark Liberty Intl. Airport, returning Sat, Dec 5, priced at $287 found 10 hours ago
Tue, Dec 1 - Fri, Dec 4
STL
Lambert-St. Louis Intl.
EWR
Newark Liberty Intl. Airport
$291 Roundtrip, found 1 day ago
$291
Roundtrip
found 1 day ago
Select United flight, departing Tue, Dec 1 from Lambert-St. Louis Intl. to Newark Liberty Intl. Airport, returning Fri, Dec 4, priced at $291 found 1 day ago
Tue, Dec 1 - Sat, Dec 5
STL
Lambert-St. Louis Intl.
EWR
Newark Liberty Intl. Airport
$299 Roundtrip, found 10 hours ago
$299
Roundtrip
found 10 hours 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 10 hours ago
Tue, Dec 22 - Fri, Dec 25
STL
Lambert-St. Louis Intl.
EWR
Newark Liberty Intl. Airport
$301 Roundtrip, found 1 day ago
$301
Roundtrip
found 1 day 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 1 day ago
Tue, Nov 10 - Sun, Nov 15
STL
Lambert-St. Louis Intl.
EWR
Newark Liberty Intl. Airport
$320 Roundtrip, found 3 hours ago
$320
Roundtrip
found 3 hours ago
Select United flight, departing Tue, Nov 10 from Lambert-St. Louis Intl. to Newark Liberty Intl. Airport, returning Sun, Nov 15, priced at $320 found 3 hours ago
Tue, Nov 10 - Sun, Nov 15
STL
Lambert-St. Louis Intl.
EWR
Newark Liberty Intl. Airport
$330 Roundtrip, found 3 hours ago
$330
Roundtrip
found 3 hours ago
Select United flight, departing Tue, Nov 10 from Lambert-St. Louis Intl. to Newark Liberty Intl. Airport, returning Sun, Nov 15, priced at $330 found 3 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.