Originally Posted by
stifle
This misunderstanding is quite often perpetuated around Facebook groups; I am slightly surprised to see it here.
The correct statement is that the UK CAA says airlines should (my emphasis) seat under-12s within one row of an adult in the same party. That would include, for example, child in 29B and adult in 30K.
Now, on a day to day basis as mentioned elsewhere BA is very good at going above the minimum, though it isn't an absolute entitlement.
Yes a bad choice of wording on my part, in terms of saying ‘have to’. However the below is on the BA website under family seating.
If you don’t choose your seats in advance, we always do our best to seat your family together. This may mean that you’ll be seated in adjacent rows or across the aisle. All children under 12 will be seated with an accompanying adult. Anyone over 12 may be seated separately.