Southwest Airlines is refusing to sign its new lease for terminal space at the San Antonio International Airport. City Council approved an airline operating agreement and several terminal leases on Thursday, but the Dallas-based carrier objected to the terms. A Southwest spokesman says the council had earlier promised to expand the new Terminal C from six gates to ten. He says the airline won't sign the new ten-year lease unless changes are made. San Antonio airport officials say seven of eight airlines have signed a lease deal.