[blunte]

There are probably enough people of financial means who are willing to pay for expensive and much faster taxi service, especially if they can go to the roof of the building they're currently in to depart.

There are lots of reasons why this won't work, but it could work... and it could be quite useful in the right scenario.

Lots of useful long distance flights leave early in the morning, meaning to get to the airport for those flights you have to leave VERY early. But with an air taxi like this, it might allow you to save a couple of hours and a lot of headache.

It's not really mass-marketable though, and I doubt we could expect to see a constant stream of little air taxis buzzing around.

[nradov]

Chances are the roof of the building they're currently in will never have a heliport. Most buildings weren't designed to support the extra weight of a helipad (including equipment) plus aircraft, and the roofs are already covered with antennas and HVAC equipment.

In the foreseeable future there will only be a handful of heliports per city center. Most passengers will have to take ground transport to reach one.

[blunte]

True most buildings aren't designed for it, and they are already covered with antennas and AC units and such.

But weight is not an issue for light aircraft. For example, the Robinson R44 (4 place heli) is only 660kg empty. The Airbus taxi will be made as light as possible, so I wouldn't expect it to be much heavier.

As long as the supports for the landing pad are placed appropriately with the building structure, it shouldn't be any problem. More likely there would be the concern of accidents and the significant collateral damage they could cause.