Why “step into a car” but “step onto a plane”

Question

Why do we say stepped into a car with cars but can't say the same with planes? Instead we say stepped onto a plane.

Answer 1

Possibly because aviation language has a certain amount in common with maritime language, and we get onto a boat.

Answer 2

Scale often matters. One steps into a canoe or rowboat but onto a yacht or an ocean liner, into a car or van but onto a bus or train. Most of the aircraft most people board are large commercial airliners, not small private planes.

Answer 3

It comes down to the notion of power and self-sufficiency. If the vehicle into/onto which you're engaging is a vehicle that in the normal course of life you have a relatively decent chance of being able to be in control of, you are stepping into it—otherwise, you are stepping onto it.

If the pilot/navigator of the ship/machine is someone who requires a non-trivial amount of training in order to command it, you are likely stepping onto it. I step onto this plane. I step onto this cruise. I step onto this space shuttle.

If you are relatively able to take control of the vehicle yourself in the normal course of things, you are more likely to step into it. I get into my car. I get into my guise. I get into the situation.

Answer 4

I think your premise is faulty. I think either "into" or "onto" works just fine. Google Ngrams shows these results for the following phrases:

stepped into the plane vs. stepped onto the plane

into the plane vs. onto the plane

into the airplane vs. onto the airplane

(No hits at all for "stepped into the airplane vs. stepped onto the airplane".)

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That being said, I personally would use "onto the plane". I feel this is due to the relative size of the vehicle. If I were entering a small plane (like a two-seater) or a helicopter, I would use "into". In general, I think it's because of the feeling of being enclosed in the vehicle. So small vehicles, like cars and kayaks, get "into". Large vehicles, like commercial aircraft and cruise ships, get "onto". (I just noticed that @choster wrote the same thing in his own answer.)

Answer 5

Mentioned this elsewhere, but it seems the controlling idea is whether the user normally sits or stands. If the user is "in" the boat, it is a small boat and the user is typically sitting. If "on" the boat, users are comfortable standing. The same applies to planes, buses,trains, automobiles, and elevators. For things that are straddled - fences, horses, bicycles, farm tractors - "on" is used.

Answer 6

I think it's because, conceptually, the purpose of a plane or boat is to hold you up, where you would otherwise fall. Whereas a car or submarine is foremost simply containing you.