Translation:The Turkish airplane flies into the city.
That sounds really strange in english, nearly like a terroristic act. Can't we translate it with "arrives in/at the city? In German: Das Flugzeug fliegt in die Stadt ein. But I would prefer, that a török repülögép leszál a városba (n), the turkish airplane is landing in the city.
One civilized solution could be if there are several airports nearby, and one of them is actually in the city, close to downtown. (There are actual places where this is true). So, the speaker could be saying that the Turkish airplane goes to the downtown airport, not to the one(s) in the suburbs.
Into might be technically correct when city means also the airspace above? Any flight control guys here that might be able to shine a light onto that issue?
But it still sounds just weird, unless we really talk about a attack or accident.
That might even be the intention, so I'd prefer something with: over, above or to. Or a different verb and sentence all together.
"A város" needs some suffix or postposition because it would otherwise be indistinguishable from the actual subject "a török repülőgép". Sort of: The city flies into the turkish airplane.
The verb however does not absolutely need "be", there are sentences without, just repül, but I think it was something about perfective meaning and without it it might or might not do/finish this flight into the city. I think your second sentence should be acceptable.
"The Turkish airplane entered the city."
But it can be also understood as:
"The Turkish airplane is entering the city's airspace."
The verb berepül has some other meanings, too:
A török repülőgép berepülte a várost. -> The Turkish airplane has flown over (or covered) all parts of the city. (e.g. on a panoramic route) (airplane is subject)
A pilóta berepülte a török repülőgépet. -> The pilot has tested (test-flown) the Turkish airplane. (airplane is a direct object)
A török repülőgép berepül az országba. -> The Turkish airplane is entering the country's airspace. (airplane is subject)