Salt Lake City International Airport's customer service slogan is at issue in a trademark lawsuit against federal security agencies, who allegedly are using a version of the city's "Simpli-fly" motto.

The city, in a federal lawsuit filed Monday, claims the Department of Homeland Security and the Transportation Security Administration have been using the term "SimpliFLY" to market its security information services.

"Because of the similarity between the marks used by [the TSA] and [the airport], prospective users of the services are likely to be deceived, mistaken or confused as to the source or origin of [the TSA's] services," the suit claims.

The city's "Simpli-fly" mark was registered with the U.S. Patent and Tradmark Office in 2005 to designate the airport's telephone information services, the suit claims. The city claims it twice has asked the TSA to stop using "SimpliFLY" but the motto remains in use on marketing materials that give information on airport security procedures.