It is known that there is no commercial helicoprers capable of carrying more than 8 passengers. This makes the cost of operation very high, thus makingit unpopular in commercial operation.

So I thinked of a suggestion of producing large commercial helicopters, with 4 rotors - engine units placed at each corner of the helicopter, and supported with extension wings. The helicopter would be of 2+2 abreast layout, having capacity from 20 to 60 passengers.

This would greatly recuce the cost of helicopter travel, like that of Boeing 707 in 1950's and 747 in 1960's, so making everybody can enjoy direct and fast trips of helicopter from airport to downtown.