While attending Oxford I met a few people going through initial interview for the NETJETS program. Someone would go home basically everyday if you didn't pass each phase of the interview.

This is the process,

1. Application Screening
2. Aptitude Testing
3. Interview with NetJets

Oxford has 3 stages.

Stage 1
Essay, from what Oxford says it's like a job application.

Stage 2
Day 1 of Stage 2 will include computer based testing of your maths and physics knowledge. ATPL Ground School requires GCSE standard knowledge in these topics to Grade C or better, which are tests taken at about age 16 by British students. The assessment tests generally do not exceed GCSE standard. The BBC Bite Size website has useful GCSE revision material for maths and physics. Join the @sk Oxford Forum and use the search engine or browse previous posts to learn more about the assessment process. Applicants to this scheme will complete all assessments used for self-sponsored APPFO applicants except for the flight simulator assessment.
Day 2 of Stage 2 will include an interview. Those who are intimately familiar with the structure of the APP First Officer course and with all aspects of NetJets are likely to perform best at the interview. There is much information about both freely available online as well as thousands of web sites with helpful tips to prepare one for a job interview.