Exhibit 3.11

STATE OF DELAWARE

SECRETARY OF STATE

DIVISION OF CORPORATIONS

FILED 12:00 PM 02/29/2000

001101183 – 2118418

CERTIFICATE OF FORMATION OF

WESTERN SKY INDUSTRIES, LLC

1. The name of the limited liability company is:

Western Sky Industries, LLC

2. The address of its registered office in the State of Delaware is Corporation Trust Center, 1209 Orange Street, in the City of Wilmington, County of New Castle, Delaware, 19801. The name of its registered agent at such address is The Corporation Trust Company.

IN WITNESS WHEREOF, the undersigned has executed this Certificate of Formation of Western Sky Industries, LLC this 24th day of February, 2000.

/s/ Bruce Graben

BRUCE GRABEN

AUTHORIZED PERSON