▁was ▁limited ▁( for ▁regul atory ▁or ▁technical ▁reasons ) ▁to ▁s elling ▁only ▁ 2 5 0 ▁of ▁them ▁on ▁a ▁particular ▁flight ▁of ▁ 1 , 0 0 0 ▁miles ▁would ▁generate ▁ 2 5 0 , 0 0 0 ▁AS M s ▁on ▁that ▁flight , ▁not ▁ 3 0 0 , 0 0 0 . ▁Similarly , ▁if ▁passenger ▁seats ▁on ▁a ▁particular ▁flight ▁are ▁dedicated ▁to ▁crew ▁rest ▁purposes , ▁such ▁seats ▁would ▁not ▁be ▁included ▁in ▁the ▁calculation ▁of ▁AS M s ▁for ▁that ▁flight . ▁ ▁Rel ated ▁quantities ▁ ▁Cost ▁per ▁AS M ▁/ ▁AS K ▁( C AS M ▁/ ▁C AS K ) ▁▁ ▁C AS M ▁( or ▁C AS K ) ▁is ▁a ▁commonly ▁used ▁measure ▁of ▁unit ▁cost ▁in ▁the ▁air line ▁industry . ▁ ▁C AS M ▁is ▁expressed ▁in ▁c ents ▁to ▁operate ▁each ▁seat ▁mile ▁offered , ▁and ▁is ▁determined ▁by ▁div iding ▁operating ▁costs ▁by ▁AS M s . ▁ ▁This ▁number ▁is ▁frequently ▁used ▁to ▁allow ▁a ▁cost ▁comparison ▁between ▁different ▁air lines ▁or ▁for ▁the ▁same ▁air line ▁across ▁different ▁time ▁periods ▁( say ▁for ▁one ▁year ▁vs ▁the ▁preceding ▁year ). ▁ ▁A ▁lower ▁C AS M ▁means ▁that ▁it ▁is ▁easier ▁for ▁the ▁air line ▁to ▁make ▁a ▁profit , ▁as ▁they ▁have ▁to ▁charge ▁less ▁to ▁break ▁even . ▁ ▁A ▁low ▁C AS M , ▁however , ▁is ▁by ▁no ▁means ▁a ▁guarantee ▁of ▁profit ability . ▁Further , ▁C