In order to fly a number of single rotor units join up with one another to form a viable aircraft. Individually the units are unable to fly but this changes when they join up and co-operate in order to fulfill their mission.
More details - and videos - can be found here.
英國鐵路公司如何推動凈零排放
It would be better if the trains had good coverage of the country. Large areas have no easy connection and so cars (or buses?) and lorries are still...