which subsidiary of small planet airlines serves both katowice international airport and warsaw chopin airport ?
select distinct var_uri where brack_open dbr_Small_Planet_Airlines dbo_subsidiary var_uri sep_dot var_uri dbo_targetAirport dbr_Katowice_International_Airport sep_dot var_uri dbo_targetAirport dbr_Warsaw_Chopin_Airport sep_dot brack_close