United Flight 4576 Deals & Information (2026/2027)

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United Flight 4576 Route Deals From $73

The cheapest prices found with in the last 7 days for return flights were $134 and $73 for one-way flights to Lambert-St. Louis Intl. for the period specified. Prices and availability are subject to change. Additional terms apply.

Wed, Apr 22 - Sat, Apr 25
ORD
O'Hare Intl.
STL
Lambert-St. Louis Intl.
$134 Roundtrip, found 2 hours ago
$134
Roundtrip
found 2 hours ago
Select United flight, departing Wed, Apr 22 from O'Hare Intl. to Lambert-St. Louis Intl., returning Sat, Apr 25, priced at $134 found 2 hours ago
Mon, Apr 6 - Tue, Apr 7
ORD
O'Hare Intl.
STL
Lambert-St. Louis Intl.
$138 Roundtrip, found 2 days ago
$138
Roundtrip
found 2 days ago
Select United flight, departing Mon, Apr 6 from O'Hare Intl. to Lambert-St. Louis Intl., returning Tue, Apr 7, priced at $138 found 2 days ago
Wed, Apr 22 - Sat, Apr 25
ORD
O'Hare Intl.
STL
Lambert-St. Louis Intl.
$153 Roundtrip, found 2 hours ago
$153
Roundtrip
found 2 hours ago
Select United flight, departing Wed, Apr 22 from O'Hare Intl. to Lambert-St. Louis Intl., returning Sat, Apr 25, priced at $153 found 2 hours ago
Wed, Apr 22 - Sat, Apr 25
ORD
O'Hare Intl.
STL
Lambert-St. Louis Intl.
$164 Roundtrip, found 2 hours ago
$164
Roundtrip
found 2 hours ago
Select United flight, departing Wed, Apr 22 from O'Hare Intl. to Lambert-St. Louis Intl., returning Sat, Apr 25, priced at $164 found 2 hours ago
Thu, Apr 2 - Sun, Apr 5
ORD
O'Hare Intl.
STL
Lambert-St. Louis Intl.
$170 Roundtrip, found 2 hours ago
$170
Roundtrip
found 2 hours ago
Select United flight, departing Thu, Apr 2 from O'Hare Intl. to Lambert-St. Louis Intl., returning Sun, Apr 5, priced at $170 found 2 hours ago
Wed, Apr 22 - Sat, Apr 25
ORD
O'Hare Intl.
STL
Lambert-St. Louis Intl.
$178 Roundtrip, found 2 hours ago
$178
Roundtrip
found 2 hours ago
Select United flight, departing Wed, Apr 22 from O'Hare Intl. to Lambert-St. Louis Intl., returning Sat, Apr 25, priced at $178 found 2 hours ago
Thu, Apr 23 - Mon, Apr 27
ORD
O'Hare Intl.
STL
Lambert-St. Louis Intl.
$180 Roundtrip, found 2 hours ago
$180
Roundtrip
found 2 hours ago
Select United flight, departing Thu, Apr 23 from O'Hare Intl. to Lambert-St. Louis Intl., returning Mon, Apr 27, priced at $180 found 2 hours ago
Wed, Apr 22 - Sat, Apr 25
ORD
O'Hare Intl.
STL
Lambert-St. Louis Intl.
$185 Roundtrip, found 2 hours ago
$185
Roundtrip
found 2 hours ago
Select United flight, departing Wed, Apr 22 from O'Hare Intl. to Lambert-St. Louis Intl., returning Sat, Apr 25, priced at $185 found 2 hours 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.