When you factor in airport queues, taxis etc., not wrong
Compared with a private flight (=Porsche) and the train it looks like below for the road-distance of 400 Km (the private flight doesn't suffer from airport queues and other trouble):
By airplane, traveling speed 110 kts in 7000 ft:
Drive to airfield: 30 Minutes
Get the papers from the tower (logbook etc) and check papers: 10 minutes
Pull the airplane out of the hangar: 15 minutes
Outside check, engine check, oil refill : 15 minutes
Eventually fuel up: 20 minutes (depends on fuel level)
Cockpit check, engine start, taxiing: 10 minutes
Flight to Oberpaffenhofen (nearby München. München International Airport is way to expensive to land):
104 minutes
taxi to parking lot: 5 minutes
checkout, secure airplane, paperwork, landing payment: 20 minutes
waiting for taxi: 15 minutes
taxi to city: 20 minutes
costs: one way flight: 227 Euros
taxi: 60 Euros
total: 244 minutes one way, with good weather conditions and no refueling assumed.
Pure flight time is great compared to the train. But all the other fuzz ...
By train:
Drive to railway station in Aschaffenburg: 60 Minutes including walk from parking area to railway station
Train:
163 minutes from Aschaffenburg to München city. No taxi reqired, by subway my customer is just 5 minutes away.
Subway: 5 minutes
total: 228 Minutes one way.
However: with the delay of 60 minutes it was
288 minutes ...
Costs: train 160 Euros one way
Drive to railway station @ 30ct/km: 12 Euros
Depending on your hourly rate the flight is already better even if the train is in time. Including the train delay the flight is clearly the better choice. But uncertainties (weather etc.) are worse with a private flight and for saftey reasons it's to arrive before sunset so you have to plan for an earlier day time for the trip.
Time for flight planning, NOTAMs check and weather report was not included.
But buying a Deutsche Bahn ticket at the PC is a one hour battle as well ...
And apparently, there are also quite some uncertainties with Deutsche Bahn to consider.