Green’s Dictionary of Slang

(a) (US black/drugs) a marijuana cigarette [it gets one high adj.¹ (3)].

1943		D. Burley N.Y. Amsterdam Star-News 22 May 11: Each was solid with his parachute, mellow and ready to glide.
1944		D. Burley Orig. Hbk of Harlem Jive 65: None of these fine young fryers all squatting on them fine soft tops is got a parachute.

(b) (drugs) a mixture of crack plus heroin or phencyclidine [the ‘slowness’ of the heroin or phencyclidine reduces the ‘speed’ of the crack].

1993		Lerner et al. Dict. of Today’s Words.
1994		M. McAlary Good Cop Bad Cop 95: He is doing Eight Balls, parachutes, cocaine, and heroin.
2001		ONDCP Street Terms 16: Parachute — Crack and PCP smoked; heroin; smokable crack and heroin mixture.