Answer:Johnny's disguise idea because he doesn't want to cut his hair that he took so long to grow and that it symbolizes that he is a greaser.
Explanation :
In chapter 4, Ponyboy and Johnny flee from their hometown and travel to Windrixville, where they hide out in an abandoned church on Jay Mountain. In chapter 5, Johnny goes to the store to buy supplies and returns to the abandoned church with a bottle of peroxide. Ponyboy panics as Johnny flicks open his knife and explains to Pony that the police have their descriptions. He tells Ponyboy, "We're gonna cut our hair, and you're gonna bleach yours" (Hinton, 61). Ponyboy initially refuses to allow Johnny to alter his appearance, and says, "Oh, no! . . . No, Johnny, not my hair!" . ***Ponyboy takes pride in his long, silky hair because it is what distinguishes him as a greaser. Pony's hair is a significant part of his identity, and he refers to it as his "trademark." ***Johnny then explains to Ponyboy that it is better than having the police cut their hair, which is something that they will definitely do once they catch them. Johnny finally convinces Ponyboy to let him cut and bleach his hair, which makes Ponyboy miserable and depressed.