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 1 day ago
$189
Roundtrip
found 1 day ago
Select United flight, departing Thu, May 14 from Portland Intl. Jetport to Washington Dulles Intl., returning Sun, May 17, priced at $189 found 1 day 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
Thu, May 14 - Sun, May 17
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$220 Roundtrip, found 1 day ago
$220
Roundtrip
found 1 day ago
Select United flight, departing Thu, May 14 from Portland Intl. Jetport to Washington Dulles Intl., returning Sun, May 17, priced at $220 found 1 day ago
Fri, Jan 23 - Sat, Jan 24
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$225 Roundtrip, found 1 hour ago
$225
Roundtrip
found 1 hour ago
Select United flight, departing Fri, Jan 23 from Portland Intl. Jetport to Washington Dulles Intl., returning Sat, Jan 24, priced at $225 found 1 hour ago
Thu, Feb 5 - Sat, Feb 7
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$230 Roundtrip, found 1 day ago
$230
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 $230 found 1 day ago
Fri, Jan 23 - Sat, Jan 24
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$235 Roundtrip, found 1 hour ago
$235
Roundtrip
found 1 hour ago
Select United flight, departing Fri, Jan 23 from Portland Intl. Jetport to Washington Dulles Intl., returning Sat, Jan 24, priced at $235 found 1 hour ago
Thu, Jan 22 - Sun, Jan 25
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$235 Roundtrip, found 1 hour ago
$235
Roundtrip
found 1 hour ago
Select United flight, departing Thu, Jan 22 from Portland Intl. Jetport to Washington Dulles Intl., returning Sun, Jan 25, priced at $235 found 1 hour ago
Sat, Mar 14 - Fri, Mar 20
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$247 Roundtrip, found 6 days ago
$247
Roundtrip
found 6 days ago
Select United flight, departing Sat, Mar 14 from Portland Intl. Jetport to Washington Dulles Intl., returning Fri, Mar 20, priced at $247 found 6 days ago
Thu, May 14 - Sun, May 17
PWM
Portland Intl. Jetport
IAD
Washington Dulles Intl.
$249 Roundtrip, found 1 day ago
$249
Roundtrip
found 1 day ago
Select United flight, departing Thu, May 14 from Portland Intl. Jetport to Washington Dulles Intl., returning Sun, May 17, priced at $249 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.