▁tight ▁fit ▁on ▁the ▁wire / t ube ▁supports . ▁ ▁The ▁approach ▁was ▁used ▁widely ▁on ▁early ▁air plan es , ▁and ▁has ▁the ▁advantage ▁of ▁light ▁weight ▁with ▁relatively ▁low - techn ology ▁materials . ▁ ▁It ▁is ▁sometimes ▁called ▁" bird ▁c age " ▁construction ▁because ▁the ▁support ▁looks ▁similar ▁to ▁closely ▁spac ed ▁w ires ▁used ▁in ▁construction ▁of ▁bird ▁c ages , ▁and ▁because ▁the ▁wire / t ube ▁support ▁outline ▁shows ▁through ▁once ▁the ▁fabric ▁is ▁tight . ▁ ▁Some ▁dis adv antages ▁of ▁this ▁approach ▁are ▁the ▁cost ▁of ▁construction , ▁due ▁to ▁the ▁many ▁inter connected ▁supports ; ▁and ▁that ▁the ▁shape ▁is ▁that ▁of ▁many ▁flat ▁pan els , ▁which ▁limits ▁smooth ness ▁of ▁the ▁skin ▁and ▁thus ▁limits ▁the ▁aer od ynam ics . ▁ ▁In ▁the ▁ 1 9 7 0 s , ▁the ▁People ▁Power ed ▁Ve h icle ▁was ▁produced . ▁It ▁was ▁a ▁two - se at , ▁" soci able " ▁tan dem ▁with ▁a ▁steel ▁sub ▁frame ▁and ▁m old ed ▁pl astic ▁body . ▁It ▁was ▁well ▁designed ▁and ▁we ighed ▁something ▁over ▁; ▁a ▁recently ▁restored ▁version ▁we igh s ▁. ▁ ▁However , ▁it ▁had ▁fla ws ▁in ▁the ▁execution ▁that ▁do omed ▁it ▁as ▁a ▁practical , ▁every day ▁vehicle . ▁Pos itive ▁features , ▁such ▁as ▁easily ▁adjust able ▁and ▁comfortable ▁seats , ▁independent ▁ped alling ▁for ▁both ▁passenger ▁and ▁driver , ▁ade qu ate ▁cargo ▁space ▁and ▁relatively ▁good ▁weather ▁protection