fly means to stay in style. so..
stay fly means to stay in style
"i gotta stay fly-y-y-y-y-y
till i die-e-e-e-e-e" - Stay Fly Three 6 Mafia
To always be high,and do it in STYLE!
"I gotta stay fly-y-y-y-y-y-y-y-y, 'til I die-e-e-e-e-e-e-e-e!