Depends on what class of airspace you are in and weather you are flying under IFR or with some kind of flight following & flight plan. But even then the air ways can be stacked vertically.
If you are flying vfr and in an airspace where that is allowed, you can pretty much go where you want as long as you stay away from controlled areas. Basically most helicopters fly VFR. The recent accident with Kobe Bryant involved a VFR flying helicopter flying into fog in LA.
True, but to provide reliable commuting you pretty much have to fly IFR, especially in a place like SF Bay or LA. This is because often marine layer clouds don't clear until 10am and people want to be at work long before then.
It may be possible to do a lot more to improve the availability of IFR approaches and routes if we factor in automated systems. It's going to take a lot longer to build more airports, but I can tell you that pretty much every airport manager in the United States will be thrilled to face that problem.
If you are flying vfr and in an airspace where that is allowed, you can pretty much go where you want as long as you stay away from controlled areas. Basically most helicopters fly VFR. The recent accident with Kobe Bryant involved a VFR flying helicopter flying into fog in LA.