Why are flights operated by some airlines more likely to be delayed than others?

If you use Google Flights, flights operated by some airlines are annotated with a red note, which is something like the following:
flights operated by this airline are usually delayed 30+ min
I wonder why some airlines (e.g. Aeroflot, Asiana) are more likely to be delayed than others.
At least the Korean Air doesn't have this tag as frequently, so it is not necessarily the problem on the airport, I assume. But I might get it wrong. But there should definitely be a difference.
So what makes some airlines end up in more delayed flights than others? They are not LCC.
Best Answer
Delay is the difference between scheduled and actual time. So, the more an airline misses the time it scheduled for arrival or departure, the more delay it has. Briefly, it means that they are not managing to perform as announced. It does not matter if they are a Low Cost Carrier (LCC) or not, late is late, although there are different metrics for what counts as a delay.
The issue is that the airline must operate a profitable schedule and that influences their plans which can be more or less agressive. They harder they try at a quick turn-around between flights in order to maximize efficiency, the more risk there is of delay.
Here is a very interesting article about the reason for flight delays and how several airlines claim to have the best on-time performance. It goes into more detail and technicalities than this answer.
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