[nickff]

It seems that the salary schedule is out of line with the actual value of the employee's labor (assuming that there is no widespread irrational behaviour in the industry). This could be related to a skills development plateau, decreased attitude/attention/enthusiasm, or possibly even risk-aversion in older employees.

[Retric]

A lot of aerospace involves government contracting which has all sorts of accounting games. Companies generally don't want highly skilled workers they want cheap workers they can bill as highly skilled. Remember cost overruns are only a bad thing if you don't get paid.

Also, the industry has a lot's of ups and down and far more recent grads than available positions.