United Flight 4576 Deals & Information (2026/2027)

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United Flight 4576 Route Deals From $59

The cheapest prices found with in the last 7 days for return flights were $157 and $59 for one-way flights to Lambert-St. Louis Intl. for the period specified. Prices and availability are subject to change. Additional terms apply.

Tue, May 19 - Sat, May 23
ORD
O'Hare Intl.
STL
Lambert-St. Louis Intl.
$157 Roundtrip, found 1 day ago
$157
Roundtrip
found 1 day ago
Select United flight, departing Tue, May 19 from O'Hare Intl. to Lambert-St. Louis Intl., returning Sat, May 23, priced at $157 found 1 day ago
Sat, May 2 - Tue, May 5
ORD
O'Hare Intl.
STL
Lambert-St. Louis Intl.
$192 Roundtrip, found 2 days ago
$192
Roundtrip
found 2 days ago
Select United flight, departing Sat, May 2 from O'Hare Intl. to Lambert-St. Louis Intl., returning Tue, May 5, priced at $192 found 2 days ago
Mon, Apr 27 - Thu, Apr 30
ORD
O'Hare Intl.
STL
Lambert-St. Louis Intl.
$199 Roundtrip, found 3 days ago
$199
Roundtrip
found 3 days ago
Select United flight, departing Mon, Apr 27 from O'Hare Intl. to Lambert-St. Louis Intl., returning Thu, Apr 30, priced at $199 found 3 days ago
Sat, May 2 - Tue, May 5
ORD
O'Hare Intl.
STL
Lambert-St. Louis Intl.
$209 Roundtrip, found 2 days ago
$209
Roundtrip
found 2 days ago
Select United flight, departing Sat, May 2 from O'Hare Intl. to Lambert-St. Louis Intl., returning Tue, May 5, priced at $209 found 2 days ago

Frequently asked questions

What route does flight number UA4576 take?
Flight number UA4576 operates non-stop from ACK to Newark, NJ Airport (EWR-Liberty Intl.). During this trip, you'll be in the air for approximately 1 hour and 40 minutes. Consider booking ahead to lock in your favorite seat.
What kind of plane is on flight number UA4576?
There's every chance you'll be cruising aboard the Canadair (Bombardier) Regional Jet 550 if you have a seat on flight UA4576. Typically, this flight leaves from Nantucket, MA Airport (ACK-Nantucket Memorial) and comes in to land at EWR.
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 UA4576 flight with Travelocity, please visit our Customer Service Portal.