I am (currently) a Design Engineering Manager in a major European A/c company but have been a subbie for the vast majority of my career, so here is my own very personal viewpoint.....
1. Sub-contracting. I have gained a lot of experience, had a lot of variety (aircraft, ships, satellites, airships) and (should have) earned a fair amount of money. I have also been lucky to have some quite responsible positions. In my particular case, I would say that this experience helped very much to get this current position. But.....
....it generally does not lead to a stable family situation and the world is changing, certainly with regards to Airbus and Boeing. They are pushing the rates down and any sub-contracting is more likely to be with their various levels of suppliers who are being tightly squeezed already.
2. With regards to Airbus. It is there intention, and they are well on their way, to become overall aircraft architects and integrators. Their direct involvement in design (structure, systems, etc) will become less. So if you can get in, and it is more difficult at the moment, then the career paths are becoming better developed and more supportive of getting high potential young 'uns in manager and aircraft architect positions quicker. I can't really add anything to the salary discussions going on.
So my recommendation would be....
- if you are interested in engineering design (structures, system installation, stress, etc.) then look to the suppliers (either just design or design and manufacture - GKN, Spirit, etc.) and even consider sub-contracting
- if you are interested in a career with Boeing or Airbus then talk to their HR departments first and look at specialising in one of the following areas...
- Flight Physics (aero, loads, perfo, etc.)
- Design and development management (configuration, project management, integration, requirements management, etc.)
- Overall aircraft architect (broad knowledge)
Hope it helps