. ▁So ▁to ▁keep ▁down ▁the ▁top ▁speed ▁of ▁a ▁large ▁engine , ▁the ▁fan ▁must ▁spin ▁more ▁slowly . ▁The ▁fan ▁is ▁driven ▁by ▁a ▁tur bine ▁off ▁the ▁same ▁sh aft , ▁so ▁the ▁tur bine ▁bl ades ▁also ▁spin ▁round ▁more ▁slowly . ▁ ▁Oper ations ▁In ▁practice , ▁the ▁oper ational ▁sav ings ▁inher ent ▁in ▁flying ▁fewer ▁aircraft ▁make ▁larger ▁types ▁more ▁econom ical ▁on ▁routes ▁which ▁can ▁sust ain ▁their ▁size . ▁ ▁However , ▁ground ▁facilities ▁such ▁as ▁run ways , ▁handling ▁facilities ▁and ▁hang ars ▁must ▁be ▁en larg ed ▁to ▁co pe , ▁and ▁the ▁exp ense ▁of ▁this ▁must ▁be ▁offset ▁against ▁the ▁lower ▁operating ▁cost . ▁The ▁limited ▁width ▁available ▁at ▁some ▁air ports ▁restrict s ▁the ▁wing ▁span ▁achiev able ▁on ▁a ▁practical ▁aircraft . ▁ ▁Reg ul atory ▁definitions ▁In ▁the ▁reg ulation ▁of ▁air ▁activity , ▁authorities ▁pose ▁additional ▁rules ▁and ▁restrictions ▁on ▁types ▁above ▁a ▁certain ▁size . ▁ ▁The ▁American ▁Federal ▁A viation ▁Administration ▁defines ▁a ▁large ▁aircraft ▁as ▁any ▁aircraft ▁of ▁more ▁than ▁ ▁maximum ▁certific ated ▁take off ▁weight . ▁ ▁The ▁European ▁A viation ▁Saf ety ▁Agency ▁( E AS A ) ▁defines ▁a ▁large ▁aircraft ▁as ▁either ▁" an ▁aer op lane ▁with ▁a ▁maximum ▁take - off ▁mass ▁of ▁more ▁than ▁ ▁or ▁a ▁multi - eng ined ▁hel ic opter ." ▁ ▁History ▁The ▁first ▁practical ▁aircraft ▁were ▁bal lo ons , ▁used ▁for ▁sport ▁and ▁for ▁military ▁observation . ▁In