This is an interesting subject, far from a joke. Airline pilots bear a few blue collar traits (hourly pay, heavy in technical tasks requiring less than an undergraduate education for example), but those are the minority in my view and the rest are white collar indicators such as makes discretionary decisions based on combinations of higher education or lengthy experience without direct supervision. Supervises the work of other professionals might be another.
A few years ago when Wichita was decimated by massive layoffs I was working as an engineer and found it necessary to determine what kind of engineer I was. White collar for sure, but there are subcategories namely, salaried exempt or salaried non-exempt by state labor laws. That's irrelevant but what I found in the state law was surprisingly detailed descriptions of what makes a worker fall into one subgroup or another. They were detailed, lawyer-quality descriptions of the subject down to seemingly nit-picking things like determines their own working hours, makes 25% or more of their own decisions without immediate review, handles large items of monetary value without supervision on a regular basis while making decisions using education obtained primarily from a combination of multi-year apprenticeship and/or graduate studies, on and on. They had it all worked out and there was no doubt what kind of worker you are.