Flights from Chicago to Allentown

Cheapest flights from Chicago

These prices were available within the past 7 days. Prices quoted are per person, round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Thu, Aug 28 - Mon, Sep 8

ORD

O'Hare Intl.

PHL

Philadelphia Intl.

$120 Roundtrip, found 5 hours ago

$120

Roundtrip

found 5 hours ago

Select Frontier Airlines flight, departing Thu, Aug 28 from O'Hare Intl. to Philadelphia Intl., returning Mon, Sep 8, priced at $120 found 5 hours ago

Thu, Aug 28 - Sun, Sep 7

ORD

O'Hare Intl.

PHL

Philadelphia Intl.

$127 Roundtrip, found 5 hours ago

$127

Roundtrip

found 5 hours ago

Select Frontier Airlines flight, departing Thu, Aug 28 from O'Hare Intl. to Philadelphia Intl., returning Sun, Sep 7, priced at $127 found 5 hours ago

Fri, Aug 29 - Thu, Sep 4

MDW

Midway Intl.

PHL

Philadelphia Intl.

$129 Roundtrip, found 5 hours ago

$129

Roundtrip

found 5 hours ago

Select Frontier Airlines flight, departing Fri, Aug 29 from Midway Intl. to Philadelphia Intl., returning Thu, Sep 4, priced at $129 found 5 hours ago

Sun, Aug 31 - Sun, Sep 7

ORD

O'Hare Intl.

PHL

Philadelphia Intl.

$134 Roundtrip, found 5 hours ago

$134

Roundtrip

found 5 hours ago

Select Frontier Airlines flight, departing Sun, Aug 31 from O'Hare Intl. to Philadelphia Intl., returning Sun, Sep 7, priced at $134 found 5 hours ago

Fri, Sep 19 - Sun, Sep 21

ORD

O'Hare Intl.

PHL

Philadelphia Intl.

$135 Roundtrip, found 3 days ago

$135

Roundtrip

found 3 days ago

Select Frontier Airlines flight, departing Fri, Sep 19 from O'Hare Intl. to Philadelphia Intl., returning Sun, Sep 21, priced at $135 found 3 days ago

Fri, Aug 29 - Fri, Sep 5

MDW

Midway Intl.

PHL

Philadelphia Intl.

$136 Roundtrip, found 5 hours ago

$136

Roundtrip

found 5 hours ago

Select Frontier Airlines flight, departing Fri, Aug 29 from Midway Intl. to Philadelphia Intl., returning Fri, Sep 5, priced at $136 found 5 hours ago

Sat, Aug 30 - Sun, Aug 31

ORD

O'Hare Intl.

PHL

Philadelphia Intl.

$146 Roundtrip, found 5 hours ago

$146

Roundtrip

found 5 hours ago

Select American Airlines flight, departing Sat, Aug 30 from O'Hare Intl. to Philadelphia Intl., returning Sun, Aug 31, priced at $146 found 5 hours ago

Thu, Sep 18 - Thu, Sep 25

ORD

O'Hare Intl.

PHL

Philadelphia Intl.

$146 Roundtrip, found 3 days ago

$146

Roundtrip

found 3 days ago

Select Frontier Airlines flight, departing Thu, Sep 18 from O'Hare Intl. to Philadelphia Intl., returning Thu, Sep 25, priced at $146 found 3 days ago

Thu, Sep 18 - Fri, Sep 26

ORD

O'Hare Intl.

PHL

Philadelphia Intl.

$154 Roundtrip, found 3 days ago

$154

Roundtrip

found 3 days ago

Select Frontier Airlines flight, departing Thu, Sep 18 from O'Hare Intl. to Philadelphia Intl., returning Fri, Sep 26, priced at $154 found 3 days ago

Thu, Sep 18 - Mon, Sep 29

ORD

O'Hare Intl.

PHL

Philadelphia Intl.

$157 Roundtrip, found 3 days ago

$157

Roundtrip

found 3 days ago

Select Frontier Airlines flight, departing Thu, Sep 18 from O'Hare Intl. to Philadelphia Intl., returning Mon, Sep 29, priced at $157 found 3 days ago

Sat, Sep 20 - Tue, Sep 23

ORD

O'Hare Intl.

PHL

Philadelphia Intl.

$157 Roundtrip, found 2 days ago

$157

Roundtrip

found 2 days ago

Select United flight, departing Sat, Sep 20 from O'Hare Intl. to Philadelphia Intl., returning Tue, Sep 23, priced at $157 found 2 days ago

Sat, Sep 20 - Tue, Sep 23

ORD

O'Hare Intl.

PHL

Philadelphia Intl.

$157 Roundtrip, found 2 days ago

$157

Roundtrip

found 2 days ago

Select American Airlines flight, departing Sat, Sep 20 from O'Hare Intl. to Philadelphia Intl., returning Tue, Sep 23, priced at $157 found 2 days ago

Fri, Sep 19 - Fri, Sep 26

ORD

O'Hare Intl.

PHL

Philadelphia Intl.

$162 Roundtrip, found 3 days ago

$162

Roundtrip

found 3 days ago

Select Frontier Airlines flight, departing Fri, Sep 19 from O'Hare Intl. to Philadelphia Intl., returning Fri, Sep 26, priced at $162 found 3 days ago

Fri, Sep 19 - Mon, Sep 29

ORD

O'Hare Intl.

PHL

Philadelphia Intl.

$165 Roundtrip, found 3 days ago

$165

Roundtrip

found 3 days ago

Select Frontier Airlines flight, departing Fri, Sep 19 from O'Hare Intl. to Philadelphia Intl., returning Mon, Sep 29, priced at $165 found 3 days ago

Sat, Sep 20 - Tue, Sep 23

ORD

O'Hare Intl.

PHL

Philadelphia Intl.

$167 Roundtrip, found 2 days ago

$167

Roundtrip

found 2 days ago

Select United flight, departing Sat, Sep 20 from O'Hare Intl. to Philadelphia Intl., returning Tue, Sep 23, priced at $167 found 2 days ago

Sat, Sep 20 - Sat, Sep 20

ORD

O'Hare Intl.

PHL

Philadelphia Intl.

$191 Roundtrip, found 3 days ago

$191

Roundtrip

found 3 days ago

Select Delta flight, departing Sat, Sep 20 from O'Hare Intl. to Philadelphia Intl., returning Sat, Sep 20, priced at $191 found 3 days ago

Wed, Sep 10 - Tue, Sep 16

ORD

O'Hare Intl.

ABE

Lehigh Valley Intl.

$221 Roundtrip, found 1 day ago

$221

Roundtrip

found 1 day ago

Select Delta flight, departing Wed, Sep 10 from O'Hare Intl. to Lehigh Valley Intl., returning Tue, Sep 16, priced at $221 found 1 day ago

Sat, Aug 30 - Sun, Aug 31

ORD

O'Hare Intl.

PHL

Philadelphia Intl.

$229 Roundtrip, found 5 hours ago

$229

Roundtrip

found 5 hours ago

Select Spirit Airlines flight, departing Sat, Aug 30 from O'Hare Intl. to Philadelphia Intl., returning Sun, Aug 31, priced at $229 found 5 hours ago

Sat, Aug 30 - Sun, Aug 31

ORD

O'Hare Intl.

PHL

Philadelphia Intl.

$284 Roundtrip, found 5 hours ago

$284

Roundtrip

found 5 hours ago

Select JetBlue Airways flight, departing Sat, Aug 30 from O'Hare Intl. to Philadelphia Intl., returning Sun, Aug 31, priced at $284 found 5 hours ago

Fri, Sep 12 - Mon, Sep 15

ORD

O'Hare Intl.

TTN

Mercer

$284 Roundtrip, found 6 days ago

$284

Roundtrip

found 6 days ago

Select Frontier Airlines flight, departing Fri, Sep 12 from O'Hare Intl. to Mercer, returning Mon, Sep 15, priced at $284 found 6 days ago