The paper offers a rigorous analysis of Milton Friedman’s parable of the ‘helicopter’ drop of money – a permanent/irreversible increase in the nominal stock of fiat base money which respects the intertemporal budget constraints of the Central Bank, the Treasury and the consolidated State. One example is a temporary fiscal stimulus funded permanently through an increase in the stock of base money. Another one is permanent QE – an irreversible, monetized open market purchase by the Central Bank of Treasury debt or private debt, when it is recognised that this permanent up-front open market purchase will have to be followed sooner or later by public spending increases or tax cuts, to ensure that the intertemporal budget constraints of the Central Bank and the Treasury remain satisfied. Three conditions must be satisfied for a helicopter money drop always to boost aggregate demand. First, there must be benefits from holding fiat base money other than its pecuniary rate of return: that is, the interest rate on any additional base money issued is below the rate of return on the Central Bank’s assets: central banking, and specifically Central Bank balance sheet expansion, is profitable. Second, fiat base money is irredeemable – viewed as an asset by the holder but not as a liability by the issuer. Third, the price of money is positive. Given these three conditions, there always exists – even in a permanent liquidity trap – a combined (set of) monetary and fiscal policy action(s) that boosts private demand (or public demand) – in principle without limit. Under these conditions, a helicopter money drop will not cause ‘policy insolvency’: the Central Bank does not lose control of the size of its balance sheet or of the inflation rate. Deflation, ‘lowflation’ and secular stagnation are therefore policy choices.