From what I remember one of the key factors in IR35 is can you be replaced, i.e. if your run your own business, could you provide another member of staff to do your work, or is the job contingent on you doing the work? For an IT consultant it's possible to find someone with similar skills that you could theoretically substitue in to do your work. As an airline pilot in the UK, with all the hoops required to get a criminal record check, airside pass, sim checks etc etc I'd say the substitution is nigh on impossible.