Sculpted side walls, a cabin that's four inches wider than its predecessor, pressurization that alleviates jet lag -- plus, every passenger can see out the window.

This is the promise of the new Boeing 777X, a hotly anticipated next-generation aircraft that is coming closer to readiness, in the first full mock-ups of its interior.

The new aircraft's possible internal configuration was on display at the recent Aircraft Interiors Expo 2019 (AIX) in Hamburg, Germany.

Interest in the new Boeing remains high, despite the continued investigation into Boeing's 737 Max airplane -- which remains grounded following two fatal air crashes.

Overshadowed by the recent tragedies, the first fully built 777X was unveiled at a low-key event in March.

At AIX, the focus was on the positives of the 777X concept and how it will deliver improved levels of passenger experience, compared to earlier versions of the venerable Boeing aircraft.

"We've learned a lot since the 777 was first introduced in the 1990s, especially a lot into human psychology during travel," Boeing cabin experience and revenue analysis regional director Kent Craver, tells CNN Travel.

"We as humans are fascinated with flight. We want to celebrate that and reintroduce the magic of flying."

This vision is reflected in the 777X design, explains Craver, as he gives a tour of the mock-up cabin interior.

New design

Each cabin is four inches wider than its equivalent on board the Boeing 777.Courtesy Boeing

The cabin on display at AIX is incomplete. While the renderings accompanying this story illustrate what the cabin will eventually look like, there are no seats at AIX. Instead, stools are used to allow attendees to preview the experience.

But the lighting, windows and curved interiors give a sense of what this aircraft might be like when it's ready and soaring the skies.

"We use lighting and the architecture to create not only physical space, which is finite, but a sense of spaciousness -- so on a psychological level," says Craver.

"We don't get into the details of how we actually are utilizing that or achieving that, we feel that's a very closely guarded trade secret for us."

The curved interior is designed to add spaciousness.Courtesy Boeing

What Craver will confirm is that the side walls are specially sculpted to curve, creating a slightly different shape to what passengers are used to.

Additionally, there's the fact each cabin is four inches wider -- which could mean more space for passengers in economy.

And there's the windows. They've been positioned higher on the fuselage, to ensure every passenger can catch a glimpse of the clouds.

"This is roughly the height of a seat," says Craver, as he sits on one of the stools in the AIX mock-up. "You can turn sideways and see outside and see the most important thing, see the horizon, see the sky."

Boeing is also promoting windows that utilize a dimming effect, already in use on its 787 Dreamliners.

On the 777X, lower pressurization will also be implemented to help passengers feel more comfortable.

There's going to be lower pressurization to help passengers feel comfortable.Courtesy Boeing

"That helps eliminate symptoms associated with being at higher altitude -- headaches, muscle aches, fatigue, nausea," says Craver.

When it comes to the overhead cabins, the 777X aims for a sleek, streamlined look.

"The 777 heads with volume -- but the volume didn't necessarily match the size and shape of luggage -- and people don't really care about volume," says Craver. "They want to know, does my bag fit? And does it fit close to my seat?"

The overhead bins on the 777X are designed for bags loaded side-on. Courtesy Boeing

The overhead bins on the 777X accommodate bags positioned on their side -- Craver says this ensures the luggage fits, but also helps the cabin appear spacious.

A similar concept was touted by Airbus at AIX -- the company is encouraging passengers to load their roll-on suitcases on their sides in its new Airspace XL bins, with the same aim of creating more space for more bags.

Flexibility

First delivery of the Boeing 777X is due in 2020.

Courtesy Boeing

Boeing says the 777X will provide flexibility for airlines, part of its vision for the future of aircraft.

"Because it's a lighter cabins, it gives airlines more space. [It] just depends on what product they want to offer," says Craver.

"We don't build seats, we don't choose what configuration -- those are all airline choices. What we want to provide is a platform that gives them that flexibility to do what they need."

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Those decisions are taking place now. The Boeing 777X enters flight testing later in 2019 ahead of its first delivery in 2020.

So what does Boeing hope to discover during the flight tests?

"The flight tests are standard flight tests for airworthiness, we do have an aircraft that will have an interior installed so we'll see how the interior components feel," says Craver.