Question: Has there ever a period in history when people were nice to each other and not killing each other?

In other words, since humans arrived, have the inhabitants of this planet ever enjoyed ***world peace***?

To answer this, we first have to define *period*. Let's define *period* as a minimum of 50 years. If there are any periods of time without records, we will have to ignore those periods.

Now let's define *not killing each other*. By this, I mean no known battles, wars, or genocides on planet earth. I'm not referring to individual acts of violence.

*As a curious side note, with over 5,000 questions asked on this StackExchange site, this is the first question to ever implement the [peace](/questions/tagged/peace "show questions tagged 'peace'") tag. Well... almost... I just realized that I don't have enough rep to create a new tag, so perhaps a moderator will be kind enough to add it.*

Answer: 
MiG, Sukhoi, Tupolev, Yakovlev, Ilyushin, Mil, Kamov, Beriev, Antonov were design bureaus, not manufacturers. It was totally common if a certain factory would produce planes of Tupolev and Ilyushin designs at the same time. 

Why several design bureaus? Possibly because of different personalities and methods of the chief designers. A person who had sufficient achievements would be given a team to guide. And the team's volume was limited by the leader's physical capabilities.

It is also to note that while the purpose of the planes could be interchangeable, there were differences in approach. For instance, Antonov produced civil airliners, like Tupolev and Ilyushin. But they specialized on planes with the wing on the top of fuselage while Tupolev and Ilyushin designed planes with the wing on the bottom. Tupolev designed narrow-body aircrafts, while Ilyushin designed both narrow and wide-bodied.

All of the design bureaus and plants were the subsidiaries of the respective Ministry of Aviation Industry.
There is no difference between central planning and capitalism. You can see an overview here:

<http://www.sjsu.edu/faculty/watkins/stalinmodel.htm>

Each firm in the Soviet economy resembled a capitalist firm, had to sell products, and bought intermediate goods and labor on the market. Although there were technically "quotas", they made no practical difference to the firm's behavior in the vast majority of cases. There was also public housing, education, and similar government activities performed in capitalist countries.

From this you can see that the answer to "why did the Soviet economy do X?" type questions can be answered by "the same reason everyone else did that".