It is Glastonbury 2024, and you've got a front-row spot for the headline act, the Rolling Stones, concluding their fifth farewell tour. You need a drink badly, so you get out your smartphone and dial up a drone, which within minutes delivers a plastic bottle from the bar a mile away.

Science fiction? Not necessarily, after the online retailer Amazon revealed that it had written to the US Federal Aviation Authority (FAA) asking to test drones that could fly at up to 50mph and for 30 minutes at a time to deliver packages weighing up to 5lb (2.3kg).

In the letter (pdf), Amazon's head of public policy, Paul Misener, says that "in the past five months we have made advancements towards the development of highly automated aerial vehicles" for its new service, which it calls Amazon Prime Air. Misener says the five-pound limit covers 86% of products sold on Amazon.

Meanwhile, the FAA's British counterpart told the Guardian that it could foresee a time when, once drones have proven their airworthiness and ability to avoid obstacles safely, they would be allowed to operate autonomously. Under current legislation, Britain bans drones from being used within 50 metres of a building or person, and insists they must remain within line of sight – typically 500 metres – of the operator.

"The line of sight provision could go away some time in the future when we see a device able to make decisions about avoiding whatever objects are out there," said a Civil Aviation Authority spokesman. "They would also have to avoid other aerial obstacles, of course." Would-be operators would have to demonstrate the potential safety of their devices to the CAA to win permission.

Given a 25-mile range, Amazon's drones could serve an area of nearly 2,000 sq miles – far greater than the 609 sq miles inside the M25, which has a maximum radius of less than 20 miles.

Future improvements to drones could mean they would be available to all sorts of companies, according to one academic expert. Darren Ansell, aerospace engineering lead at the University of Central Lancashire, said: "A pizza company might not want to own and operate drones – so you could have operators offering a sort of transportation or postal-style service."

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