Unfortunately, it doesn't matter.
The bigger, household name airlines, do not care what you did before you qualified. They might spout stuff about being commercially aware, but that's not true either.
There are simple requirements, which are:
- you meet a certain age demographic
- you went to a certain school
- you reached/ or are predicted to reach a certain standard when training
- you reach the required standard at the airlines selection board/interview
If you don't have the above, then you will find contacts being the next best way in. For the others, there is a lottery of sending CVs, visiting, applying etc.