Today on ST, we continue our three-part series of conversations with the leading candidates to be the City of Tulsa's next mayor. As per changes to the City Charter that were enacted in 2011, the current race for mayor will be non-partisan, with a primary scheduled for Tuesday of next week: June 11th. If no candidate receives 50 percent of the vote in this primary, the top two vote-recipients will meet up in the general election, in the fall --- and if any one candidate gets more than 50 percent of the vote in this primary, that person will become our next mayor (to serve a three-year term beginning in early December). Yesterday we heard from Kathy Taylor, the former Mayor of Tulsa; on tomorrow's show, we will hear from Tulsa's current Mayor, Dewey Bartlett. Our guest on this edition of StudioTulsa is Bill Christiansen, who served on the Tulsa City Council, representing District 8, from 2002 to 2011. Christiansen also runs an aviation company here in Tulsa, Christiansen Aviation, which opened for business in 1972. He's a graduate of the University of Oklahoma and was a Marine Corps Reserve officer.