United Flight 4478 Deals & Information (2026/2027)

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United Flight 4478 Route Deals From $149

The cheapest prices found with in the last 7 days for return flights were $195 and $149 for one-way flights to Washington Dulles Intl. for the period specified. Prices and availability are subject to change. Additional terms apply.

Fri, Sep 4 - Mon, Sep 7
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$195 Roundtrip, found 4 days ago
$195
Roundtrip
found 4 days ago
Select United flight, departing Fri, Sep 4 from Portland Intl. Jetport to Washington Dulles Intl., returning Mon, Sep 7, priced at $195 found 4 days ago
Thu, Feb 5 - Sat, Feb 7
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$204 Roundtrip, found 5 days ago
$204
Roundtrip
found 5 days ago
Select United flight, departing Thu, Feb 5 from Portland Intl. Jetport to Washington Dulles Intl., returning Sat, Feb 7, priced at $204 found 5 days ago
Fri, Sep 4 - Mon, Sep 7
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$204 Roundtrip, found 4 days ago
$204
Roundtrip
found 4 days ago
Select United flight, departing Fri, Sep 4 from Portland Intl. Jetport to Washington Dulles Intl., returning Mon, Sep 7, priced at $204 found 4 days ago
Sat, Sep 5 - Mon, Sep 7
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$210 Roundtrip, found 4 days ago
$210
Roundtrip
found 4 days ago
Select United flight, departing Sat, Sep 5 from Portland Intl. Jetport to Washington Dulles Intl., returning Mon, Sep 7, priced at $210 found 4 days ago
Sat, Sep 5 - Mon, Sep 7
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$220 Roundtrip, found 4 days ago
$220
Roundtrip
found 4 days ago
Select United flight, departing Sat, Sep 5 from Portland Intl. Jetport to Washington Dulles Intl., returning Mon, Sep 7, priced at $220 found 4 days ago
Fri, Jan 23 - Fri, Jan 30
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$222 Roundtrip, found 3 days ago
$222
Roundtrip
found 3 days ago
Select United flight, departing Fri, Jan 23 from Portland Intl. Jetport to Washington Dulles Intl., returning Fri, Jan 30, priced at $222 found 3 days ago
Fri, Jan 23 - Sat, Jan 24
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$225 Roundtrip, found 4 days ago
$225
Roundtrip
found 4 days ago
Select United flight, departing Fri, Jan 23 from Portland Intl. Jetport to Washington Dulles Intl., returning Sat, Jan 24, priced at $225 found 4 days ago
Fri, Jan 23 - Fri, Jan 30
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$232 Roundtrip, found 3 days ago
$232
Roundtrip
found 3 days ago
Select United flight, departing Fri, Jan 23 from Portland Intl. Jetport to Washington Dulles Intl., returning Fri, Jan 30, priced at $232 found 3 days ago
Thu, Feb 12 - Sun, Feb 15
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$236 Roundtrip, found 1 day ago
$236
Roundtrip
found 1 day ago
Select United flight, departing Thu, Feb 12 from Portland Intl. Jetport to Washington Dulles Intl., returning Sun, Feb 15, priced at $236 found 1 day ago
Fri, Sep 4 - Mon, Sep 7
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$247 Roundtrip, found 4 days ago
$247
Roundtrip
found 4 days ago
Select United flight, departing Fri, Sep 4 from Portland Intl. Jetport to Washington Dulles Intl., returning Mon, Sep 7, priced at $247 found 4 days ago
Thu, Feb 12 - Sun, Feb 15
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$250 Roundtrip, found 1 day ago
$250
Roundtrip
found 1 day ago
Select United flight, departing Thu, Feb 12 from Portland Intl. Jetport to Washington Dulles Intl., returning Sun, Feb 15, priced at $250 found 1 day 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.