United Flight 1521 Deals & Information (2026/2027)

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United Flight 1521 Route Deals From $284

The cheapest prices found with in the last 7 days for return flights were $297 and $284 for one-way flights to Denver Intl. for the period specified. Prices and availability are subject to change. Additional terms apply.

Tue, Aug 18 - Sun, Aug 23
DAY
James M. Cox Dayton Intl.
DEN
Denver Intl.
$297 Roundtrip, found 3 days ago
$297
Roundtrip
found 3 days ago
Select United flight, departing Tue, Aug 18 from James M. Cox Dayton Intl. to Denver Intl., returning Sun, Aug 23, priced at $297 found 3 days ago
Fri, Jul 10 - Mon, Jul 13
DAY
James M. Cox Dayton Intl.
DEN
Denver Intl.
$299 Roundtrip, found 14 hours ago
$299
Roundtrip
found 14 hours ago
Select United flight, departing Fri, Jul 10 from James M. Cox Dayton Intl. to Denver Intl., returning Mon, Jul 13, priced at $299 found 14 hours ago
Tue, Apr 21 - Sat, Apr 25
DAY
James M. Cox Dayton Intl.
DEN
Denver Intl.
$302 Roundtrip, found 1 hour ago
$302
Roundtrip
found 1 hour ago
Select United flight, departing Tue, Apr 21 from James M. Cox Dayton Intl. to Denver Intl., returning Sat, Apr 25, priced at $302 found 1 hour ago
Thu, Jul 9 - Sun, Jul 19
DAY
James M. Cox Dayton Intl.
DEN
Denver Intl.
$307 Roundtrip, found 2 days ago
$307
Roundtrip
found 2 days ago
Select United flight, departing Thu, Jul 9 from James M. Cox Dayton Intl. to Denver Intl., returning Sun, Jul 19, priced at $307 found 2 days ago
Sat, May 23 - Sat, May 30
DAY
James M. Cox Dayton Intl.
DEN
Denver Intl.
$311 Roundtrip, found 14 hours ago
$311
Roundtrip
found 14 hours ago
Select United flight, departing Sat, May 23 from James M. Cox Dayton Intl. to Denver Intl., returning Sat, May 30, priced at $311 found 14 hours ago
Fri, Jul 10 - Mon, Jul 13
DAY
James M. Cox Dayton Intl.
DEN
Denver Intl.
$313 Roundtrip, found 14 hours ago
$313
Roundtrip
found 14 hours ago
Select United flight, departing Fri, Jul 10 from James M. Cox Dayton Intl. to Denver Intl., returning Mon, Jul 13, priced at $313 found 14 hours ago
Tue, Apr 21 - Sat, Apr 25
DAY
James M. Cox Dayton Intl.
DEN
Denver Intl.
$326 Roundtrip, found 1 hour ago
$326
Roundtrip
found 1 hour ago
Select United flight, departing Tue, Apr 21 from James M. Cox Dayton Intl. to Denver Intl., returning Sat, Apr 25, priced at $326 found 1 hour ago
Thu, May 7 - Tue, May 12
DAY
James M. Cox Dayton Intl.
DEN
Denver Intl.
$329 Roundtrip, found 5 hours ago
$329
Roundtrip
found 5 hours ago
Select United flight, departing Thu, May 7 from James M. Cox Dayton Intl. to Denver Intl., returning Tue, May 12, priced at $329 found 5 hours ago
Sat, Jun 20 - Tue, Jun 23
DAY
James M. Cox Dayton Intl.
DEN
Denver Intl.
$329 Roundtrip, found 5 days ago
$329
Roundtrip
found 5 days ago
Select United flight, departing Sat, Jun 20 from James M. Cox Dayton Intl. to Denver Intl., returning Tue, Jun 23, priced at $329 found 5 days ago
Thu, Jun 11 - Sun, Jun 21
DAY
James M. Cox Dayton Intl.
DEN
Denver Intl.
$330 Roundtrip, found 2 days ago
$330
Roundtrip
found 2 days ago
Select United flight, departing Thu, Jun 11 from James M. Cox Dayton Intl. to Denver Intl., returning Sun, Jun 21, priced at $330 found 2 days ago
Wed, Jul 8 - Wed, Jul 22
DAY
James M. Cox Dayton Intl.
DEN
Denver Intl.
$331 Roundtrip, found 22 hours ago
$331
Roundtrip
found 22 hours ago
Select United flight, departing Wed, Jul 8 from James M. Cox Dayton Intl. to Denver Intl., returning Wed, Jul 22, priced at $331 found 22 hours ago
Tue, Apr 21 - Sat, Apr 25
DAY
James M. Cox Dayton Intl.
DEN
Denver Intl.
$332 Roundtrip, found 1 hour ago
$332
Roundtrip
found 1 hour ago
Select United flight, departing Tue, Apr 21 from James M. Cox Dayton Intl. to Denver Intl., returning Sat, Apr 25, priced at $332 found 1 hour ago
Sat, May 23 - Sat, May 30
DAY
James M. Cox Dayton Intl.
DEN
Denver Intl.
$336 Roundtrip, found 14 hours ago
$336
Roundtrip
found 14 hours ago
Select United flight, departing Sat, May 23 from James M. Cox Dayton Intl. to Denver Intl., returning Sat, May 30, priced at $336 found 14 hours ago
Tue, Apr 21 - Sat, Apr 25
DAY
James M. Cox Dayton Intl.
DEN
Denver Intl.
$336 Roundtrip, found 1 hour ago
$336
Roundtrip
found 1 hour ago
Select United flight, departing Tue, Apr 21 from James M. Cox Dayton Intl. to Denver Intl., returning Sat, Apr 25, priced at $336 found 1 hour ago
Thu, May 7 - Tue, May 12
DAY
James M. Cox Dayton Intl.
DEN
Denver Intl.
$338 Roundtrip, found 5 hours ago
$338
Roundtrip
found 5 hours ago
Select United flight, departing Thu, May 7 from James M. Cox Dayton Intl. to Denver Intl., returning Tue, May 12, priced at $338 found 5 hours ago
Thu, May 7 - Tue, May 12
DAY
James M. Cox Dayton Intl.
DEN
Denver Intl.
$338 Roundtrip, found 5 hours ago
$338
Roundtrip
found 5 hours ago
Select United flight, departing Thu, May 7 from James M. Cox Dayton Intl. to Denver Intl., returning Tue, May 12, priced at $338 found 5 hours ago
Wed, Apr 1 - Mon, Apr 6
DAY
James M. Cox Dayton Intl.
DEN
Denver Intl.
$339 Roundtrip, found 17 hours ago
$339
Roundtrip
found 17 hours ago
Select United flight, departing Wed, Apr 1 from James M. Cox Dayton Intl. to Denver Intl., returning Mon, Apr 6, priced at $339 found 17 hours ago

Frequently asked questions

What route does flight number UA1521 take?
UA1521 jets between IAD and CLE directly. This trip takes 1 hour and 14 minutes.
How often is UA1521 on time?
United Airlines flight number UA1521 between IAD and Hopkins Intl. Airport (CLE) runs on schedule 91% of the time — so you can relax knowing that you will reach your destination ASAP. If your service is delayed, you're likely to wait approximately 44 minutes. This route has a star rating of 2.75.
What kind of plane is on flight number UA1521?
Get set to cruise the skies aboard a Boeing 737-800 if your flight number is UA1521. Almost all flights from Dulles Intl. Airport to CLE use this aircraft type.
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 UA1521 flight with Travelocity, please visit our Customer Service Portal.