United Flight 4478 Deals & Information (2026/2027)

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United Flight 4478 Route Deals From $129

The cheapest prices found with in the last 7 days for return flights were $189 and $129 for one-way flights to Washington Dulles Intl. for the period specified. Prices and availability are subject to change. Additional terms apply.

Thu, May 14 - Sun, May 17
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$189 Roundtrip, found 10 hours ago
$189
Roundtrip
found 10 hours ago
Select United flight, departing Thu, May 14 from Portland Intl. Jetport to Washington Dulles Intl., returning Sun, May 17, priced at $189 found 10 hours ago
Fri, Sep 4 - Mon, Sep 7
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$195 Roundtrip, found 7 hours ago
$195
Roundtrip
found 7 hours ago
Select United flight, departing Fri, Sep 4 from Portland Intl. Jetport to Washington Dulles Intl., returning Mon, Sep 7, priced at $195 found 7 hours ago
Fri, Feb 6 - Tue, Feb 10
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$202 Roundtrip, found 3 days ago
$202
Roundtrip
found 3 days ago
Select United flight, departing Fri, Feb 6 from Portland Intl. Jetport to Washington Dulles Intl., returning Tue, Feb 10, priced at $202 found 3 days ago
Thu, Feb 5 - Sat, Feb 7
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$204 Roundtrip, found 1 day ago
$204
Roundtrip
found 1 day ago
Select United flight, departing Thu, Feb 5 from Portland Intl. Jetport to Washington Dulles Intl., returning Sat, Feb 7, priced at $204 found 1 day ago
Fri, Sep 4 - Mon, Sep 7
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$204 Roundtrip, found 7 hours ago
$204
Roundtrip
found 7 hours ago
Select United flight, departing Fri, Sep 4 from Portland Intl. Jetport to Washington Dulles Intl., returning Mon, Sep 7, priced at $204 found 7 hours ago
Sat, Sep 5 - Mon, Sep 7
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$210 Roundtrip, found 7 hours ago
$210
Roundtrip
found 7 hours ago
Select United flight, departing Sat, Sep 5 from Portland Intl. Jetport to Washington Dulles Intl., returning Mon, Sep 7, priced at $210 found 7 hours ago
Sat, Sep 5 - Mon, Sep 7
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$220 Roundtrip, found 7 hours ago
$220
Roundtrip
found 7 hours ago
Select United flight, departing Sat, Sep 5 from Portland Intl. Jetport to Washington Dulles Intl., returning Mon, Sep 7, priced at $220 found 7 hours ago
Fri, Jan 23 - Sat, Jan 24
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$225 Roundtrip, found 16 hours ago
$225
Roundtrip
found 16 hours ago
Select United flight, departing Fri, Jan 23 from Portland Intl. Jetport to Washington Dulles Intl., returning Sat, Jan 24, priced at $225 found 16 hours ago
Thu, May 14 - Sun, May 17
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$230 Roundtrip, found 10 hours ago
$230
Roundtrip
found 10 hours ago
Select United flight, departing Thu, May 14 from Portland Intl. Jetport to Washington Dulles Intl., returning Sun, May 17, priced at $230 found 10 hours ago
Fri, Jan 23 - Sat, Jan 24
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$235 Roundtrip, found 16 hours ago
$235
Roundtrip
found 16 hours ago
Select United flight, departing Fri, Jan 23 from Portland Intl. Jetport to Washington Dulles Intl., returning Sat, Jan 24, priced at $235 found 16 hours ago

Frequently asked questions

What route does flight number UA4478 take?
UA4478 takes roughly 2 hours and 1 minute to jet directly from STL to IAD. We all know there's magic in the destination, but half the fun is in the journey!
What terminal does UA4478 fly out of?
Passengers on flight number UA4478 from STL to IAD typically fly out of Terminal 1.
What kind of plane is on flight number UA4478?
The Canadair (Bombardier) Regional Jet 550 is the type of aircraft most commonly used for flight number UA4478. This flight almost always leaves from Lambert Field and lands at IAD.
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 UA4478 flight with Travelocity, please visit our Customer Service Portal.