AltoVolo is up, up, and away. 

The London-based firm has built and flown a quarter-scale prototype of its Sigma aircraft, with a full-scale demonstrator due for completion at the end of the year. 

Unveiled in May 2025, the Sigma is a hybrid VTOL (vertical takeoff and landing) aircraft with seriously impressive performance specs. In fact, AltoVolo has dubbed it the world’s first “HyperTOL,” on account of its high-performance nature. 

Unlike eVOTLs, which are fully electric, Sigma is equipped with a hybrid-electric propulsion system, meaning it can run on either battery power or fuel. The compact craft, which measures roughly 13 feet from nose to tail and weighs just 2,160 lbs, can fly 500 miles in hybrid mode or 250 miles in electric. It can also reach a top speed of up to 220 mph at an elevation of up to 10,000 feet, while making 80 percent less noise than a helicopter, according to AltoVolo. 

These figures, only estimates at this stage, mean the Sigma could fly faster and farther than many eVOTLs on the market. By comparison, Archer Aviation’s Midnight tops out at 150 mph and 100 miles. It is worthwhile noting that many of these electric competitors are intended to serve as air taxis, completing short, emission-free flights in rapid succession with quick charges in between. The Sigma, on the other hand, is more akin to a private helicopter. It looks cool, too, with a sleek, sports car-like design that is more interesting than the average chopper.

The cabin, which measures 16 feet wide, can accommodate two passengers, plus luggage. Sport Pilot certificate holders will be able to take the helm with just 25 hours of training, but they will be restricted to flying only in fair weather conditions and during daylight hours in most cases. 

AltoVolo says it has nailed down the details of the first production aircraft and is now focusing on detailed engineering and certification. It is targeting full type certification for the Sigma in the commercial aircraft category. There is no telling how long that complicated process will take, but the firm says having close ties with certifying bodies in Europe and the U.S. is helping with the timely progression towards approvals.

Click here to see more photos of the Sigma.