Today’s invention is a flying train. Well, actually it’s a plane with a fuselage in two parts: a cigar-shaped inner (blue) and a normal airliner’s rear section (grey) into which the front section fits.
On landing, the blue inner would engage with an electric railway undercarriage and take passengers and their luggage (or urgent freight) straight to some metropolitan centre.
The rear section could then be refitted to another passenger module when it arrives, at bullet train speed, at the airport.
Passengers would thus enjoy uninterrupted high-speed transport from city to city, allowing this hybrid transport system to fill the gap between trains and planes over medium-length routes eg in Europe.