▁Port land , ▁Port land , ▁August a , ▁and ▁Bang or . ▁Its ▁leg ▁from ▁Bang or ▁to ▁Cal ais ▁is ▁often ▁referred ▁to ▁as ▁" The ▁Air line " ▁commonly ▁thought ▁to ▁be ▁due ▁to ▁its ▁shorter ▁route ▁than ▁the ▁older ▁U . S . ▁ 1 . ▁( Before ▁the ▁coming ▁of ▁air ▁travel , ▁the ▁term ▁air line ▁often ▁referred ▁to ▁such ▁a ▁shortcut .) ▁Although ▁an ec d otes ▁about ▁un expl oded ▁ord n ance ▁der iving ▁from ▁bom bers ▁flying ▁from ▁the ▁former ▁Dow ▁Air ▁Force ▁Base ▁( now ▁Bang or ▁International ▁Airport ) ▁using ▁a ▁number ▁of ▁to wers ▁and ▁land marks ▁along ▁" The ▁Air line ", ▁in ▁fact ▁the ▁term ▁goes ▁back ▁to ▁the ▁early ▁ 1 8 5 0 s ▁as ▁a ▁contrast ▁to ▁the ▁sh or eline ▁route . ▁The ▁last ▁section ▁of ▁" The ▁Air line " ▁was ▁p aved ▁in ▁ 1 9 7 3 ▁in ▁C raw ford ▁and ▁many ▁old ▁sections ▁of ▁the ▁road ▁are ▁visible ▁to ▁the ▁side ▁of ▁the ▁present ▁road way . ▁ ▁The ▁" Wh ale ' s ▁Back ", ▁a ▁ 2 - mile ▁stretch ▁built ▁at op ▁an ▁es ker ▁in ▁Han cock ▁County ▁was ▁one ▁of ▁the ▁most ▁notable ▁features ▁of ▁the ▁highway ▁until ▁it ▁was ▁re built . ▁ ▁Over ▁the ▁years , ▁a ▁number ▁of ▁improvements ▁have ▁been ▁made ▁by ▁the ▁Route ▁ 9 ▁Committee , ▁a ▁partners hip ▁of ▁local ▁government ▁officials ▁and ▁business ▁interests ▁in ▁the