Green’s Dictionary of Slang

one who robs vehicles.

1781		G. Parker View of Society n.p.: The Rum Dragger generally follows broad-wheel waggons on horse-back, and counterfeiting drunkenness, rides up against the shaft-horses [etc.].
1937		E. Raymond Marsh 50: It was the van draggers that pinched the whole outfit.
1956		‘Charles Raven’ Und. Nights 85: A dragger, i.e., a hook who steals luggage from parked cars.
1970		R. Fabian Anatomy of Crime 193: Dragger: Steals from vehicles.
2004		N. ‘Razor’ Smith A Few Kind Words and a Loaded Gun 76: George could hot-wire it and drive it away quick as a wink [...] and was fast gaining a reputation as a pukka wheel-man, or ‘dragger’.