Flowcopter promises an extraordinary 900 km (560 miles) of range and more than six hours of endurance, as well as a huge 150 kg (330 lb) max payload. It's built for an ultra-long range niche, particularly targeted at making deliveries to super-remote settlements and offshore oil rigs, as well as extended search and rescue missions and long-endurance agricultural use.

These use cases simply can't be filled with all-electric powertrains – the specific energy in lithium-ion batteries pales in comparison to what fossil fuels can deliver. But combustion engines aren't well suited to delivering the near-instant torque adjustments required to balance a multicopter in the air.