Deffkoptas
"Wot's faster than a warbuggy, more killy than a warbike, and flies through da air like a bird? I got no bleedin' idea, but I'm gonna find out."
-Kog da Flymek, pioneer of the Deffkopta
Alternatively:
"Harharhar! Humie don' surf!"
No, but seriously
A Deffkopta is an Ork flying device resembling a crude helicopter or gyrocopter built to seat one, the pilot, and carry a set of underslung weaponry, generally twin-linked big shootas, bazookas or mega-blastas. The vehicle usually has additional rocket thrusters installed on it to aid the velocity-addicted greenskin manning it to get his nonexistent rocks off even harder than already possible, notwithstanding how senseless jamming rockets onto a helicoper is (unless they're the shoot-at-the-other-guy kind). Some daring flyboys go so far as to modify their rawket lawnchair with a chainsaw or rotary saw blade sticking out the bottom to driveby-slit-up gits with, unheeding of the danger of snagging it on something and then slamming face first into the ground. It is the logical extension of the average Kult of Speed fanatics' MO and one would not at all be wrong to think of it as essentially being an airborne Waaaghbike, sometimes even being constructed from the remains of one (though that doesn't mean much with orks anyway).
So it came to pass that in the 41st millenium, as the humans were rocking a transport craft that was the Mil Mi-24 Hind in design, carrying capacity, combat role and armament but exactly not name, the Orks were still the only ones with any actual helicopters.