Translation:The airplane is flying over these cities.
It's correct Hungarian, and both are required because that's how Hungarian does it.
(Why does English say "five apples", with a required plural ending on "apples" even though that's redundant given that "five" already says that there is more than one? Because that's just how English does it. Hungarian, on the other hand, doesn't: öt alma.)
To me, "over these cities" implies movement starting on one side of the cities, with its midpoint directly above them, and ending at a point past the cities, while fölött does not have this movement meaning and only indicates that the flying takes place over/above the cities at all times.
Maybe "over" could be used in the "location, not direction" meaning as well, as long as you don't confuse yourself that fölött indicates this "from one side to the other" meaning (as in "he stepped over the dog").
Yes there is...:
"Demonstratives and postpositions
Hungarian has one more complication in store for you. When you combine a demonstrative and a noun like ez a ház ‘this house’ with a postposition like mellett ‘next to‘, the resulting form is like with the case suffixes above:
emellett a ház mellett ‘next to this house’
afölött a kert fölött ‘above that garden’"
Sorry to correct you. But we write them separately in this case.
E mellett a ház mellett ‘next to this house’ A fölött a kert fölött ‘above that garden’
Emellett, amellett, efölött, afölött etc. are adverbs.
I'm too tired to go for a walk. Besides, it's raining. Túl fáradt vagyok, hogy sétálni menjek, emellett még esik is.
Yes sorry I thought I had replied to my own comment but not sure where it's gone now! I saw that there was an explanation, although perhaps it's a design flaw (in my opinion) that these are presented as a kind of optional extra that you have to remember to read, rather than something that's integral to your learning.
DL is a free resource. There are good teachers and courses out there (another heads up for the Debrecen Summer School - but it is not cheap let alone free).
You can read the tips and sentence discussions or ask specific questions (I have not idea what you mean by "I dont understand anything").
Another cheap alternative is to buy a grammar book - but first you need to know what you don't know.
Later lessons build on this though. Ezek will become ezeknél, ezekbõl, ezektõl, etc.
Fölött has fölé, fölül.....
That's further down, though.
What you need to know first is:
A városok fölött. - above the city.
Ez fölött a város fölött. - above this city.
Ezek fölött a városok fölött. - above these cities.
The fölött would also need to go after the article when specifying a selection or a group. It's a Hungarian grammar rule that kind of stresses that these cities are the target or what you are saying, and it also surrounds the noun target.