According to some speakers of English language, the use of in and on in transportation is one of the ‘weirdness’ of prepositions. Despite this difficulty, we’ve found a simplified way of explaining it.
It is however necessary to know that we might not know how this solution was found, but we found it and it’s correct.
On a lighter note, who cares about ‘why’ when we know ‘how’ and we’re right?
The way out
When you get into a car, you sit immediately; when you get into a bus, you have a larger space, so you move to your seat.
Therefore, we get ‘on’ a large floor space or a space without wall (on a stage, on a bike, on a skateboard, on a ship, on a plane), but we get ‘in’ a car, a small boat, a helicopter, etc.
- We met on a bus en route Nairobi.
- Tom sat quietly in the car as police officers approached him.
- Don’t get on a boat if you’re scared.