All that empty space inside to move in zero G would be fun. Just add some padding and nets to avoid injuries.
So much of this article refers to 2017 as being in the future.
This is opposite of the typical cargo planes, which often are older passenger planes or derived types that still have cabin pressurization.
It depends on what you're delivering. For the large airplane parts they are designed for, pressurization isn't needed.
Though Mriya's cargo weight capacity is 250t, 190t is the heaviest single item it's lifted (a power station gas generator, from Poland to Armenia).
Speaking of the Pelican Effect, see the Boeing Pelican (concept only) https://en.wikipedia.org/wiki/Boeing_Pelican
The predecessor to the Beluga XL was the Beluga (in the early 90s), and before that Airbus used Super Guppies. They bought two, then bought the right to build them and built two more.
However XL has more than twice the cargo volume.
While it was refitted and is active again, the An-225 was a strategic plane with the singular purpose of transporting Buran. After he dissolution of the USSR, it was mothballed for nearly a decade.
Given its use for transporting large plane parts I’d think an airship would more cost effective. For wind turbine places and the like too, as in both cases size is a bigger barrier than weight.
I know there have been some airship projects in the past few years: why have they not succeeded?
This was not a concern here, it's not going to be sold to operators (let alone operators who don't want to retrain crew).
There are only 5 Beluga XL (likewise its predecessor) and it exists solely and exclusively for Airbus to move parts around due to the distributed nature of its production.
Before Airbus built their own cargo aircraft, they used Super Guppies, which is why there is one on display near or in two of Airbus' facilities (Toulouse and Hamburg), despite the Guppy being on a Boeing base. Airbus actually bought the right to build Guppies at the time.
The answer is that Airbus is a consortium, a prestige project of the European Union.
One consequence of this, is that parts are manufactured in multiple countries, at a considerable distance from one another, as opposed to the more consolidated approach taken by Boeing.
Therefore, they have a unique need to ship very large and somewhat delicate parts from place to place. The Beluga is a consequence of this.
FWIW Boeing built a similar plane (the 747-400 LCF / 747 Dreamlifter) to move 787 parts from suppliers, as they were considered too large for marine shipping and existing cargo planes. The biggest difference is LCF is a conversion from regular 747s (though according to wikipedia the program cost the same $1bn, being built from a much heavier plane the Dreamlifter has much higher capacity but somewhat lower volume in its similarly unpressurised hold).
The Dreamlifter is a straight up conversion of second-hand 747-400s by a contracted third-party (Evergreen Aviation Technologies Corporation).
Airplanes have a major advantage of not needing to fit through tunnels, under powerlines, or around corners.
They do use Beluga XLs to these parts around too?
Airbus ship at the Hamburg Finkenwerder factory:
The ship travels to Bordeaux and from there the parts will be brought with smaller ships to Toulouse.
edit: I found this page  where it talks about moving A380 parts to Toulouse. It sounds like it does happen via the Garonne, but not anywhere even remotely close to Toulouse!
> Here, the components are transferred to specially-designed barges, which carry them on the penultimate part of their 95 km. voyage up Garonne River from Pauillac to Langon. ... In Langon, aircraft sections are transferred to outsized-load trucks to complete their journey to Toulouse by road.
That means the wings and other components have to travel more than 200km from Langon to Toulouse by road, which is wild. Good thing a lot of that is relatively empty countryside rather than packed city streets.
A much larger version of the A-12 trips between Burbank and Area-51, which was also super cool.
e.g. here https://www.flightradar24.com/data/aircraft/f-wbxl
They run around Europe as Airbus has very distributed facilities for political reasons (it's a multinational project and thus has facilities in various countries), though mostly between Hamburg and Toulouse.
From time to time they also get chartered for non-airbus cargo: space program parts (that was a primary use case of its Super Guppy ancestor), copters to air show, relief supplies, and Liberty Leading the People between France and Japan in 1999 (as the painting was too large to fit in a 747).
I haven't seen the XL in person, yet, but the Beluga is a common sighting over Hamburg.
Have seen the older Beluga taking off and landing from Blagnac when I have been there.
> With 30% more capacity than the existing Beluga, it will be able to carry two A350 XWB wings instead of one. Its new fuselage is 6.9 m longer and 1.7 metre wider than the Beluga, and it will be able to lift a payload 6 tonnes heavier.
That list isn't in order of size.