Gravity is about a third of Earth's and competitive aerobation helicopter models have a truly excessive power surplus. Just look at this.
There won't be any manned helicopter flight. The helicopter power scales poorly with size - there's a reason we have no VTOL Jumbo Jets. But the same up-scaling issue is our friend when down-scaling. A 6kg helicopter can lift 30kg of payload, so we have equivalent of TWR=6 on Earth.
Drag and lift are both identically (quadratically) proportional to airspeed, so the same loss of lift causes loss of the primary limiting force of the helicopter - air drag on the blades. What's left is mechanical losses (friction of bearings), and mechanical durability of the construction, but these can be built with much surplus - plus larger rotor blades will offset need for extreme RPM.
Of course other things must be taken into account. These flights will be more like "hops" - a short segment of flight followed by a looong recharging period. And the drone will need to be small - and that means not much scientific equipment. Unfortunately, that also means it won't be fully autonomous as there simply won't be enough room to fit a good radio and antenna to reach Earth, or even the satellites. But it could definitely serve as a "recon vehicle" for a large rover, fetching small samples, testing firmness of ground surface for driving over, and planning the best route.
Ingenuity has performed its first flight.. Most of data in my post predicted Ingenuity's parameters correctly. 2,500 rpm at 60cm rotor radius gives 157m/s top linear speed of the rotor tips, vs 267m/s speed of sound in carbon dioxide (and 90m/s in aerobation RC helicopters), so they remained subsonic. It's lightweight - 1.8kg, comparable to heavier aerobatic models. It uses the rover as a retransmitter to contact the satellites and Earth. The rotor blades are both wider and longer than in aerobation RC helicopters to compensate for the thin atmosphere, but the motor is comparable to mid-shelf models regarding power output. The helicopter is capable of a 30s flight and requires a day to recharge the batteries.
As the first phase - technology demonstration of feasibility of powered flight on Mars has ended, Ingenuity performs reconnaissance work helping Curiosity pick interesting targets.