which subsidiary of westjet serves both halifax stanfield international airport and halifax stanfield international airport ?
select distinct var_uri where brack_open dbr_WestJet dbo_subsidiary var_uri sep_dot var_uri dbo_targetAirport dbr_Halifax_Stanfield_International_Airport sep_dot var_uri dbo_targetAirport dbr_Halifax_Stanfield_International_Airport sep_dot brack_close