I think the ILO classified air pilots the same as ships officer, in the so-called semi-professional category. (ATC's too) That I guess would make them white collar, however it is (was) a strongly unionised sector, so would be blue collar as far as management is concerned. (Where would the Aus Medical Association fit?) In ATC's case FAA recently prophesied that US ATC system would eventually be automated and operated by a handfull of engineers. They charachterised the US ATC's as over-paid blue collar workers.
Personally I think the terms are now meaningless, probably always were because there have always been professions/jobs that did not fit into that quaintly British view of the world.