The universe for the 2007 Census of Law Enforcement Aviation Units (CLEAU) was any law enforcement agency with 100 or more
sworn officers that reported operating a fixed-wing plane or helicopter in the 2003 Law Enforcement Management and Administrative Statistics (LEMAS) Survey. Based on the 2003 LEMAS, the CLEAU was sent to 245 of the 941 LEMAS agencies with 100 or more sworn officers.
The CLEAU was a paper questionnaire mailed to each agency chief. Data collection began in March 2008 and ended in September 2008. Respondents used either calendar or fiscal year 2007 for all questions referring to 2007 and the last day of calendar or fiscal year 2007 for all other questions.
Of 245 agencies, 241 (or 98%) responded. Twenty-four agencies (9.8%) no longer operated aircraft or had misreported in the 2003 LEMAS and never operated aircraft. Five agencies shared an aviation unit with another agency that had already responded, and 11 agencies had fewer than 100 sworn officers. As a result, the final CLEAU database included 201 aviation units.