During the early days of the helicopter, engineers began dreaming of a new age of regional and commuter air transport.

They imagined inner-city heliports where large 30-50-seat helicopters or even hybrids such as the rotor tip-jet-powered Fairey Rotodyne could take passengers from the middle of London or Paris to other major cities faster than even the speediest rail service. At a time when fuel prices were low and cities were enjoying major investment, the idea of helicopters operating in and out of city heliports seemed feasible.

Unfortunately, not everyone agreed; some of the new emerging designs, the impressive Rotodyne included, turned out to be extremely noisy even from a long distance; it was this factor alone that made airlines think twice about the idea. Today, city heliports do operate, but only for those few rich enough to be able to afford them.

But now the idea of using helicopters to service commuter and regional routes is beginning to re-emerge, at least in Europe and in the U.S. Factors that forced engineers to abandon the idea of rotary-wing city-center passenger services are now affecting the large airports that serve major cities. While air traffic continues to grow, concerns about noise and environmental impacts have kept airport infrastructure from growing in line with demand, resulting in airport congestion.

In the back rooms of AgustaWestland and Eurocopter, engineers are now thinking about how the helicopter could help solve or alleviate airport congestion. “If you want to build a runway and you are not in the planning phase today, you will probably not have it until the late 2020s,” says Lutz Bertling, CEO of Eurocopter.

“While it appears to be a mainly European issue, it is not that much different in the U.S. and Canada. Of course in some areas it is easy to create additional capacity, but in others it is more crowded—take the [U.S.] East Coast for example,” he adds.

Bertling and others believe that the major factor now is the constrainednumber of slots at major airports. Currently, each takeoff and landing—whether it is a 19-seat Beechcraft 1900, a 180-seat Airbus A320 or a Boeing 777—requires a runway slot. Bertling argues that it makes more sense to take smaller fixed-wing aircraft out of the equation and free up the slots to make room for larger aircraft.

“The industry has to transport more passengers per slot, which then makes you realize that it makes less sense to use that slot—which you can use for a 747—for a 50-seat turboprop.

“If you can get this traffic, with relative low numbers of passengers, off the runway you create more slots for bigger aircraft and to do this, you have two solutions: one is high-speed rail and the other is vertical lift,” he added.

In some countries high-speed rail is controversial because of the significant cost and environmental impacts, and the fact it only can link major cities. In comparison, helicopters only need a helipad at a major airport, eliminating costly railway infrastructure.

“Helicopters can fly relatively fast and the noise footprint for people living around the airport is relatively the same to the current traffic noise, so vertical lift can still play a role, providing you can design an aircraft with a higher speed at reasonable cost,” says Bertling, hinting at the use of the company's X3 technology.

Regional jets and turboprops will continue to have a place, however. Even though the X3 technology delivers faster cruise speeds than traditional helicopters, these rotorcaft are still not as fast as a turboprop. Instead, such services might be limited to feeder routes of about 180 mi. (300 km) or less.

“I believe that we could well see the first serial products which could do the job with a smaller number of passengers—say 19 seats—at the beginning of the 2020s, and I could imagine seeing larger aircraft 30-40 [seats] in the mid- 20s,” says Bertling. While the aircraft may be slightly more expensive to operate than turboprops, airlines might be able to charge a premium for such service.

Only a handful of passenger helicopter services remain around the world. One of the best-known, the Isles of Scilly helicopter service, which ran in the U.K. for more than three decades, ended in November 2012 because of increased costs. With higher speed and increased productivity however, helicopters could have a place in regional airline operations in the future.