For years tech companies such as Amazon, Alphabet and Uber have promised us delivery drones bringing goods to our doorsteps in a matter of minutes. So why are they taking so long to arrive?
One word: regulation.
If our skies are to become as crowded as our streets, airspace rules need updating to prevent accidents, terrorist attacks, and related problems, such as noise pollution.
But that's easier said than done. Here's a rundown of the main issues.
Noisy nuisances?
According to a recent study by Nasa, the noise made by road traffic was "systematically judged to be less annoying" than the high-pitched buzzing made by drones.
The locals in the Australian suburb of Bonython, Canberra thought much the same thing when Wing, Google owner Alphabet's delivery drone service, began fast-food delivery trials there.
"With the windows closed, even with double glazing, you can hear the drones," one local resident told ABC News.
Consequently, limiting noise pollution is an important consideration for regulators, many of whom have forbidden drone deliveries after dark - precisely the time many hungry householders would like that takeaway meal delivered.
"Noise pollution has been an area of debate during the drafting of the new European rules," says Yves Morier of the European Aviation Safety Agency (EASA).
Rogue drones
Even with relatively few drones in the skies, the number of potentially dangerous incidents is worryingly high.
Just last month, a "rogue" drone closed Wellington Airport in New Zealand, while a UK drone user was charged with endangering lives by flying too close to a police helicopter.
And Venezuelan President Nicolas Maduro says he was recently the target of a drone "attack".
Regulators are trying to take back control by implementing registration schemes.
"The vision is unified traffic management, digitalised, on all levels, from local to national and international," Benoît Curdy, secretary general of the Global Unmanned Aircraft Systems Traffic Management Association (GUTMA), said in September.
"Registration is the first step, as it enables the authorities to know who is flying."
European regulators are equally concerned.
"Rogue drone use is a major concern for us," says the EASA's Mr Morier.
"We cannot reduce the risk to zero, but we can take steps to limit it. These include making registration obligatory for drones weighing more than 250g."