Yesterday (28th) I was on a flight from Minsk to Prague, admittedly in Business Class. Mother was in 2B and little girl across the aisle in 2C. looked as if she was 4 or maybe 5, certainly no older. Not only was she very quiet, but she studied the safety instruction card during the briefing and was careful to keep her seat belt on - so unlike many of the 'business men' pax.
Now kids like that are NOT a problem......