Make them prove it. Cost to benefit ratio, vs. a shared leasing arrangement or air taxi.
I don’t want a government that decides which cost is acceptable.
Just like salaries, they are an expense. If they spend too much money, they can suffer like anyone that spends too much money.
If you really are conservative, you don’t want the government to make business decisions for private industry.
If they buy a jet, a jet company gets more business and they pay more taxes.