“Let us suppose now that one day a helicopter flies over this community and drops an additional $1,000 in bills from the sky, which is, of course, hastily collected by members of the community. Let us suppose further that everyone is convinced that this is a unique event which will never be repeated." (Milton Friedman, “The Optimum Quantity of Money,” 1969)
"The deflation speech saddled me with the nickname 'Helicopter Ben.' In a discussion of hypothetical possibilities for combating deflation I mentioned an extreme tactic—a broad-based tax cut combined with money creation by the central bank to finance the cut. Milton Friedman had dubbed the approach a 'helicopter drop' of money. Dave Skidmore, the media relations officer…had advised me to delete the helicopter-drop metaphor…'It’s just not the sort of thing a central banker says,' he told me. I replied, 'Everybody knows Milton Friedman said it.' As it turned out, many Wall Street bond traders had apparently not delved deeply into Milton’s oeuvre.” (Ben Bernanke, The Courage to Act, 2015, p. 64)
In previous posts, I discussed tools that the Fed might use in response to a future slowdown in the U.S. economy. I argued that, even if the scope for conventional interest-rate cuts is limited by already-low rates, the Fed has additional policy tools available, ranging from forward guidance about future rate policies to additional quantitative easing to targeting longer-term rates. Still, so long as people have the option of holding currency, there are limits to how far the Fed or any central bank can depress interest rates. Moreover, the benefits of low rates may erode over time, while the costs are likely to increase. Consequently, at some point monetary policy faces diminishing returns.
When monetary policy alone is inadequate to support economic recovery or to avoid too-low inflation, fiscal policy provides a potentially powerful alternative—especially when interest rates are “stuck” near zero  However, in recent years, legislatures in advanced industrial economies have for the most part been reluctant to use fiscal tools, in many cases because of concerns that government debt is already too high. In this context, Milton Friedman’s idea of money-financed (as opposed to debt-financed) tax cuts—“helicopter money”—has received a flurry of attention, with influential advocates including Adair Turner, Willem Buiter, and Jordi Gali.
In this post, I consider the merits of helicopter money as a (presumably last-resort) strategy for policymakers. I make two points. First, in theory at least, helicopter money could prove a valuable tool. In particular, it has the attractive feature that it should work even when more conventional monetary policies are ineffective and the initial level of government debt is high. However, second, as a practical matter, the use of helicopter money would involve some difficult issues of implementation. These include (1) the need to integrate the approach with standard monetary policy frameworks and (2) the challenge of achieving the necessary coordination between fiscal and monetary policymakers, without compromising central bank independence or long-run fiscal discipline. I propose some tentative solutions for these problems.
To be clear, the probability of so-called helicopter money being used in the United States in the foreseeable future seems extremely low. ... However, under certain extreme circumstances—sharply deficient aggregate demand, exhausted monetary policy, and unwillingness of the legislature to use debt-financed fiscal policies—such programs may be the best available alternative. It would be premature to rule them out.
[There is quite a bit more detail in the full post.]