The process started off with a recruiter call, mostly to just check in on what I had worked on in the past and see my interest in Airbnb positions. Following the initial recruiter call, I was setup with two phone screens.
The phone screens were fairly straight-forward leetcode style challenges to be completed in coderpad. Interviewers will want to jump straight into writing code shortly after introducing themselves and I suggest you get working on the problems as soon as possible.
I talked to multiple people regarding their phone screen questions and did a lot of research on what Airbnb asks - if you do your googling you will find that nearly all if not all of their phone screen questions are listed online in various places.
Onsite consisted of two coding interviews, two cross-functional interviews, one architectural interview, and one experience interview.
Coding questions were standard leetcode style questions. The two questions I was asked were not listed anywhere on glassdoor or leetcode and I had not seen either before. If you're on top of your CS fundamentals you should have no issues, but don't be afraid to discuss your ideas with your interviewers, as in both cases I received helpful feedback that guided me towards the correct solutions.
The cross-functional interviews are mostly just questions that enable them to see how you vibe with Airbnb's core values and how you would work as an employee. You will literally be rated on how well you fit each value, so I suggest you do your research and make sure you can tie your answers to each of the core values they have listed online.
My architectural interview focused solely on table design. I was surprised to see that the focus was entirely on tables as I mostly prepared for generic system design, but again, my interviewer was extremely helpful and happily explained concepts to me that I had previously not known.
Experience interview started with a short description of all the projects I'd worked on at my previous job and proceeded to an in-depth exploration of a project that I had worked on. Make sure you are fully prepared to answer any and all questions regarding design choices and motivations for your projects, as well as any tradeoffs and potential changes you would make now. This interview was particularly intense and you will be dinged if you do not have the answer to any of the interviewers questions, so make sure you know your projects like the back of your hand.
All in all I would say my interview experience was stressful, but kind of fun - people at Airbnb seemed very friendly, and all my interviewers were very helpful. Unfortunately, I made some mistakes that cost me the offer, but I certainly don't begrudge anyone at the company.
One extra thing I might add is that a recent interview posted on glassdoor suggested that there would be questions regarding discrete math and operating systems (processes, mutexes, etc). I was not asked any questions of the sort - it was good to get a refresher but I wish I had put the time I spent studying for that into preparing for experience/cross-functional interviews instead.