Employing engineers in defense has the opposite effect of a subsidy: it takes engineers out of the commercial job market thereby decreasing supply and raising prices.
From that wikipedia article you linked: "In standard supply and demand curve diagrams, a subsidy will shift either the demand curve up or the supply curve down. A subsidy that increases the production will tend to result in a lower price, while a subsidy that increases demand will tend to result in an increase in price."
Defense R&D increases the demand for engineers and thereby raises their "price". I don't know if it has a significant effect though.
The government employing engineers is strictly speaking not a subsidy. It's just an increase in demand. Yes, one type of a subsidy does result in an increase in demand. But causing an increase in demand is not a necessary&sufficient condition for being a subsidy. Because now the government is demanding engineers. It does not decrease supply. Someone who is employed is still by definition part of the labor market. The only person who is not a part of the labor market is someone permanently not looking for work.