I quit my MBB consulting job to help others land jobs at top firms. Here's what separates the candidates who get offers.

• Jack Kim struggled to break into consulting but eventually landed at an MBB firm.
• Kim quit his job at Bain to co-found a mentorship company that helps others get consulting roles.
• Kim said passing the "airplane test" is key to getting an offer.

This is an as-told-to essay based on a conversation with Jack Kim, a former Bain & Company consultant who co-founded Casebuddy, a consulting mentorship program. This story has been edited for length and clarity.

It was really hard for me to break into consulting.

I went to London School of Economics, where I did my bachelor's and master's, and then I started at a consulting firm called Parthenon, which is now part of EY. I worked there for about a year and a half and then interviewed with the MBB firms, ultimately joining Bain.

I stayed at Bain for three and a half years and got two promotions in that time. Last August was my last month in consulting. I knew I didn't see myself doing consulting for a long time. I never really saw myself becoming a partner, and I always wanted to do something entrepreneurial.

My friend was already running a mentorship business, so I decided to join him. I'd mentored loads of students from high school all the way to university and work, so I decided to give it a go.

We offer a one-on-one mentorship program that takes students from A to Z, from the very beginning of resume writing and cover letters all the way to networking, behaviorals, and case interviews. The cost of the mentorship program varies because everyone's on a different timeline and has different priorities. It ranges between 1,000 pounds, or about $1,300, all the way up to 5,000 plus pounds, or around $6,700, in super niche customized cases. Most of the students will land in between.

Our first cohort that we launched last year had fewer than 10 students. We got four of them into a top consulting firm, McKinsey, Bain, or BCG, and one of them actually came from a non-target university.

For our second quarter this year, we've had over 1,000 people apply to the mentorship program, which I'm super grateful for, but we only take 10 to 15 people because we want to make sure that we provide dedicated support to each one.

Most people are finding us through my social media presence, mostly YouTube, which I started building while I was still a consultant. It is small but growing. I also posted consistently on TikTok and Instagram last year, and hosted a free webinar that 500 people signed up for.

The biggest reason I left consulting was the feeling of fulfillment. Whilst I did enjoy the interactions and the people in consulting, I'm a very results-oriented person, and seeing the results of my students getting their jobs makes me feel fulfilled and happy.

I didn't land a job in consulting right away because I overlooked the 'airplane test'

In my final year of university, I failed seven final round interviews. I think it mostly came down to the "airplane test."

I really underestimated the importance of culture fit and behavioral interviews, which is what resulted in those failures. After not getting an offer, I had to go back to school to do a master's, which obviously cost a lot of money again, but then I finally got a job.

When I researched online, everyone talked about acing the case interviews, but no one really highlighted the importance of the behavioral interview. So I always overlooked that, and I think that's what made me essentially delay my consulting journey for a year.

The "airplane test" is a consulting terminology used in hiring. We travel a lot for our projects. So what we think about is: Can I sit next to this candidate on an airplane for 12 hours, and would I be comfortable and have fun doing it? Because I'm going to be doing that every single week on a travel project.

Passing this test will help you get the offer: Do I find this person comfortable? Do I like this person enough to see them in our team? And ultimately, next to my seat on an airplane.

It's especially important at the final round of the hiring process. Everyone's going to be really good at cases by the time you reach the final round.

Ultimately, it comes down to executive communication, being able to hold a conversation with senior partners, and at the same time just being likable and being a joy to be around.