Sorry not to be specific - but I would think your hotel can organize an electric wheelchair. Do you need it right from the airport - or can the person take a few steps in or out of a cab?

In Vienna all we did was walk - yes, quite a few cobblestones - and took the tram - which I don;t believe had any access for wheelchairs - but this was about 4 years ago.

For hotels you will have to contact and ask specifically about stairs and a handicap bath..

http://www.wien.info/en/travel-info/accessible-vienna/accessible-health

@kybourne thank you!

I was in Vienna last year. The metro had elevator access somewhere. We took elevators when we were with luggage, and we found one eventually. The cobblestone streets in Vienna were relatively smooth compared to similar pedestrian zones in Italy. The trams come in different styles. The classic trams have high floors, and it is not accessible by wheelchairs. If you wait further, the next one is probably a modern sleek one with the platform level floor you can just slide into the tram. The biggie palaces, the Hofburg and Schönbrunn are flat once you reach the apartment level. Both attract huge tour groups that block the tour passage and the view of the exhibits. The core of Vienna is a pedestrian zone and there are no sidewalks or curves. Take a look at Kärntner Straße, for example, on Google street level and you can get a feel of what the center looks like. Just around the core where the cars are allowed had curves cut at the intersections. The restaurants generally had generally good access. The tough ones were the Beisl restaurants that kept the classic interior layout. Some were very tight to get around even those on two feet. I saw a man on a walker who had to abandon his walker to go up a spiral staircase to an upstairs dining room. It wasn't clear if he was a local and that was where he always ate all his life or that his party could not find a table big enough at the ground floor level that night.

That was very helpful. Were you using a wheelchair?

The Wien Info siten quoted above has good info.
Vienna becomes more friendly to those with disabilities.
A good firm with many products including wheelchairs

Bstandig

www.bstaendig.at

they have many shops in Vienna

most central in the very city center is on Freyung 5

Major sites usually have access.
The Fine Arts Museum has chairs for rent too for visits there. This a fine but large museum .

www.khm.at

Subway / UBahn stops all have elevators judt look for signs .

city center small bus has " feature to lowe /kneel bus- make this need known to driver.

Many streetcar routes now getting new almost flat floor to ground entrance way . If not this by the first car coming - probably soon.
Numerous hotels with special feature rooms.

I think above website has a list of cafe / restaurants with easy access, but enough to be found. some perhaps with just one step.

It seems some Churches fail to have easy access

State Opera and Volksoper have special space arrangements for wheelchairs- end of an aisle with good viewing - this a nice thing for music lovers.

Enjoy the trip.