FLYING CAR, full hover, fairly quiet, offered to US Marines

But won't the neighbours moan about vertical takeoffs in the street?

As you'd expect, ground travel is more fuel efficient than flying — the Tyrannos should get more than 650 miles out of a tankful of military JP-8 on the road.

In the event of losing engine power in flight, the Tyrannos can set down safely on battery power alone. If one of the four lift fans is lost, its opposite number will automatically throttle down and be used purely for stability control: the two fans on the other axis have enough grunt to manage a safe landing. In the event of losing two fans or some other total disaster, the Tyrannos will deploy a parachute that still ought to get its passengers down in reasonably good order, with minimum destruction to anything underneath.

Plenty of room in the back with the seats folded down — handy for the cross-Channel booze cruise.

That all sounds excellent for the US Marines, of course, but we still aren't yet at the flying car for the rest of us. Noise regulations, for instance, are a huge barrier to aircraft operations — especially anywhere a lot of people live, which is by definition where people tend to want to go.

Even here, though, the Tyrannos is a strong contender. According to Logi, the engine "has a muffler system comparable to an SUV", and indeed engine noise can be temporarily eliminated altogether by use of battery-only operation (maximum 70 miles travel on the ground or 30 in the air). On the ground this means almost totally silent (and pollution/emissions free) "stealth mode" operation.

In the air the fans would still be noisy, but they are claimed to be "half as loud as comparable free propellers". Landings and takeoffs would require the engine running as well, but car engines aren't that big a deal. The Tyrannos — if not allowed to make vertical takeoffs in residential areas at night, perhaps — would at least be able to fly a lot nearer to town centres than normal aircraft before completing its journeys on the ground.

But there are other reasons why we don't all have our own light aircraft already. Just getting a basic pilot's licence requires more than 30 hours' flight time and the mastering of some quite difficult skills: flying a normal plane — let alone a chopper — is quite difficult. Then an extra instrument rating allowing a pilot to fly in cloud or rain and enter busy airspace is sufficiently expensive and time-consuming that on the whole only professional pilots bother to obtain one.

These are also problems for the US Marines, in fact. It isn't that the Marines don't have plenty of pilots, but they are all very highly-trained officers with years of flight school behind them. The idea is to use the Transformer TX like a flying jeep, to give basic air mobility to ordinary rifle companies which contain only a handful of officers — and those few without wings on their chests and fully occupied as commanders.