If your just talking about technical achievements then the A-380 is one of the better ones. Its one and only problem is it never should have been built. It was corporate welfare at its worst. https://www.forbes.com/sites/danielr.../#56cb0db33c59
There was never a need for it. Experts in the Industry warned about what would inevitable happen, it was never a viable money maker in the passenger plane market. Airports hated the thing. It needed special dual terminals built as well as maintenance hangars. It was so big just wheeling one around the tarmac caused all kinds of slow downs in operations as did the air vortex it created when landing or taking off. I believe it was in the area of 10 mins where'as another airplane could not occupy its airspace due to the turbulence it caused.
Boeing warned them even the 747 size aircraft were on their way out and the 2 engine widebodys were the future. Everyone warned them but Airbus just couldn't help themselves. Corporate welfare was a big part of it but I think the technical challenge really drove them. And to their credit they succeeded.
They succeeded in building a 4 engine Jumbo that could only make money on short hops to Mecca, or places like it, with 600 smelly pilgrims flying on the cheap for their yearly pilgrimage. There just wasn't ever the market for such a jet. I never flew on one but Ive been on them and they are very nice. I was on one that was brand spanking new once, its still had that new plane smell.
Corona didn't help its cause either. Air France and Lufthansa are retiring their fleets and I'd bet they will all be gone in the next few years. https://aviationweek.com/air-transpo...80-retirements