I think a 30 min charge time would be acceptable. Of course with electric drive vertical takeoff is simple and has already bean done, will be quiet, so city centre heliports are in plus small recharge stations can be positioned cheaply around the country. Of course with vertical takeoff/land, ballistic chuts, smaller lower drag wings can be used to give higher cruise speeds, this could be the true start of an intercity point to point air taxy service. I can only see a win win from electric drive and it will come with new battery chemistries.
A 400lb/182kg battery at 3kw/kg would store approx. 550kw at 100kw(134hp)/hr burn would be 5.5 hours to empty with a low drag design 150knots or more cruise should be possible with 825knots range over 900miles to empty. Electric motors are lighter than IC engines for same output with short term higher peek power outputs. This means the power for vertical take off is there.
Putting 500kw into a 500volt battery in 30 minutes would take 2000 amps
and forced air cooling off the battery would be needed this is all within current technology so all that is needed for viable electric aircraft is a battery of 3kw/kg or greater. Lithium air has the potential max of, 10kw/kg but after packaging it should make 3 to 4 kw/kl, this is what the car industry is aiming for and I believe it will happen as per the aircraft designed by August at Yeovil. So watch out for battery development the closer to 3kw/kg the sooner it will happen.
Romeo Tango putting an avgas or god forbid hydrogen at a million dollars a go electric is cheap, but will require a high power supply which means 3 phase of 11klvolts or greater and will still need a buffer on site or a 2000hp gen set which is very big. Battery exchange may turn out the best way to go and be leased rather purchased like a gas bottle and trucked to recharging station.
With vertical takeoff recharge stations could be positioned next to major substations so little infrastructure change needed. It's a think outside of the box a brave new century, which at the end in 2101 and will look nothing like it did in 2001.