Age cut-off for child/adult fares

[timetosmile]

We are going to Ethiopia at some point over the next few months. DS is currently 11.5yrs Some airline's seats seem to change to adult fares at twelve
Anyone around who knows if this is a universal cut-off point or if some airlines still allow 12 year olds to travel on children's fares?
Thanks

flybe cut off is 12. to be honest it made no difference to the cost though of my teenager, as child and adult prices were the same.

The majority of airlines the fare is an infant until age 2 then they pay the same fare as adults.
Some airlines still operate the 67 percent of fare for children age 2-12 but I am sure none go up older than 12.

We flew with US Airways this summer and, when booking direct on their website, they allowed a slight discount (about 100 -150 quid??) for dd who was 13 (on way out, 14 on way back). It surprised me.