Of course it's good business. World War II was one big factor of pulling US's ass out of the Great Depression. However, the short term benefit of such war-time economy goes to the big corporations. The average working Joe getes very little of that money spent by the government, other than his monthly wage. In Long-term, the benefit is blurred because many other factors that contributes to the economy other than the enormous Defense spending 5-6 years ago.
It took from Late 1930's (beginning of rearmament of US military + Lend-Lease to Allies) to Early 1950's (Baby Boom, Rise of Suburbs) to show major economic upturn. I would seriously doubt we'll see the benefit of the defense money (which is OURS.. paid by the good ole Tax Paying sheeps) in near future. However, I do see the point that Boeing and other defense contractors needing more workers and thus helping to lower unemployment.