There doesn't seem to be any dispute with the findings of various studies, that investing public dollars in most other things (education, green energy, infrastructure, healthcare, etc.), or not taxing the money from working people in the first place, produces more jobs than military spending.
In a generally wonderful new book by Clifford Conner called The Tragedy of American Science, the author claims that if a government produces more jobs through non-military spending, private capital will produce fewer jobs, more than eliminating the benefit. Only military spending, he claims, produces jobs nobody else would produce, because military spending like Great Depression-era jobs digging and then re-filling ditches produces nothing useful.
Reasons to doubt this include studies finding long-term negative impacts from increased military spending, and little negative impact from dramatically reduced military spending, not to mention the complete lack of correlation between nations' military budgets and employment rates in comparison with other nations. There's also the capacity of private individuals to purchase things that are just as useless as weapons, including in fact weapons, not to mention the mountains of non-essential crap that we're doing without during the coronavirus crisis, much to the relief of the natural environment.
And then there's the apparently unconsidered option of a universal basic income. If paying people to dig ditches and fill them in again is the key to a happy economy, then so should be paying people for being human beings who have the right to a basic subsistence, and for refraining from environmentally destructive production of useless and murderous commodities.
A global ceasefire is an opportunity to consider shifting to a completely different economy which I also take to be the point of Conner's analysis of military spending, whether or not it's right. A billion dollars spent in the United States on militarism creates 11,200 jobs compared to 17,200 in healthcare. The military spending makes us less safe, while healthcare spending protects us. The military spending generates a massive need for additional healthcare. The healthcare spending generates no need for militarism.
If we shift to spending money on things we need, like healthcare, environmental protection, non-military science, and disarmament, we can treat "the economy" as one more thing we need and spend on it directly rather than guessing at the side benefits of a gargantuan program of mass murder. If people need money, we can give it to them as a universal basic income which has the added benefits of eliminating huge quantities of bureaucracy (which, despite being as useless as weapons, does not seem to benefit us), of eliminating huge motivations for resentment against each other based on who does and doesn't qualify for non-universal programs, and of allowing people to much more readily stop the spread of deadly viruses.
The top benefit we should seek from ceasing firing in wars we cannot afford to continue during a real crisis, and from this pandemic itself, is a new understanding of universality. Not only does killing people not benefit them, but we are all in this nightmare together. What harms others harms you, and vice versa. We need, therefore, a universal economy that invests in actual defense against the danger posed to all of us by the lack of protection possessed by the least well protected among us.