"He does not travel by plane."
Translation:Він не подорожує на літаку.
Personally I'd say, подорожувати літаком is actually a better translation of "by plane", it implies plane as means of transportation (the case here is Instrumentalis)
And подорожувати на літаку sounds actually wrong to me, I never say it this way. It means literally to travel "on the plane", it implies plane as a location (the case of на літаку is Locativ), as if you were on a plane and were travelling just there, locally inside of the plane :D
Well, not to be rude, but why does it appear here that this course is teaching us incorrect Ukrainian translations in this skill? When reinforced it's going to get stuck in our brains that way. I assume that the course creators are Ukrainian speakers so I don't understand why some of the Ukrainian here is not considered correct. Seems strange, like not everyone is on the same page. Just felt I should point this out. I don't feel that way about all the skills. It's still a nice course for learning Ukrainian overall.
«На літаку» is actually not uncommon, but it's avoided because it's not a native Ukrainian form but a calque of the Russian «на самолёте».
In general, almost everyone's Ukrainian is influenced by Russian to some extent, so it's not a problem if a Russian-influenced phrase or two sticks in your brain.
(But I agree that «літаком» sounds better.)
Yes, this is as incorrect as saying "Me and Jessica" in English. It's technically wrong, you're supposed to say "Jessica and I", but a lot of people say it and it's perfectly understandable and not confusing at all meaning-wise. It's the difference between prescriptive and descriptive language. Language purists or just people who are sensitive to these things aesthetically (I am this second type) prefer "подорожувати літаком", otherwise the other version is fine.