Mutual possession with "each other"

Question

If there are two parties and each person is in possession of something belonging to the other, how do you express this in a sentence? For example, if we give them names, we can say:

Alice is driving Bob's car, and Bob is driving Alice's car.

Is it proper to say this?

They are driving each other's cars.

I'm mostly asking because this is how I would probably say it in conversation (as a native speaker in the Midwest), but when I type it out it's suggested as a typo, and now it feels kind of weird thinking about it.

Answer 1

You should certainly have a space between each and other; these are two words. There is no such English word as eachother. But if that correction is made, the sentence “They are driving each other’s cars” is perfectly fine. Consider “They are at each other’s throats” as an analogy.

If the given sentence seems too awkward when written out, however, consider “Each of them is driving the other’s car” as an alternative.

Answer 2

If they each have a car, then you MUST say: drive each other's cars.

If they only have one car between them, then you MUST say: drive each other's car.

Look here: https://dictionary.cambridge.org/grammar/british-grammar/pronouns/each-other-one-another

Lisa and Kate hated each other’s husbands. (Lisa hated Kate’s husband and Kate hated Lisa’s husband.) I hold your hand, you hold my hand. We hold each other's hands.

Answer 3

The correct sentence is: They are driving each other's car -- not cars (plural). Whenever you use "each" the object becomes singular, not plural. Each person only has one car. Notice that you wrote: each other's cars -- and not, each others' cars. So you would have to be wrong because each person only has one car.

If you mean that each person has two or more cars, and they both drive all of the other person's cars, then you can use your original sentence.