AAON, Inc., a Nevada corporation ("AAON-Nevada" or, including its subsidiaries,
the "Company" or "AAON"), was incorporated on August 18, 1987.

AAON, Inc., an Oklahoma corporation ("AAON-Oklahoma"), was incorporated on
August 15, 1988, for the purpose of acquiring the assets, subject to certain
liabilities, of the Heating, Ventilation and Air-Conditioning ("HVAC") Division
of John Zink Company in Tulsa, Oklahoma. In 1989, pursuant to a
Conversion/Exchange Agreement, AAON-Oklahoma became a wholly-owned subsidiary of
AAON-Nevada.

AAON-Oklahoma is engaged in the manufacture and sale of air-conditioning and
heating equipment consisting of rooftop units, chillers, air-handling units,
condensing units and coils.

In 1991, AAON Coil Products, Inc. ("ACP", formerly CP/AAON, Inc.), a Texas
corporation, was organized as a wholly-owned subsidiary of AAON-Nevada to
purchase most of the assets of a company in Longview, Texas. ACP manufactures
coils used in the Company's products.  ... More..."http://secfilings.nasdaq.com/edgar_conv_html%2f2004%2f03%2f12%2f0001026608-04-000016.html#FIS_BUSINESS"