A Very UK class conscious question, Surely its not the job itself its the gradations within it make the difference.
Police Officer white collar ? no chance not for the basic plod on the beat maybe Inspector and up yes.
Pilots=airline pilot clearly professional -as indicated from qualifications check ups etc etc , but an Ag pilot -well maybe thats blue collar and proudly so.
When you look at it you have to question the whole issue and which category one would like to fall into anyway
example professional footballer -Premiership- cannot string two words together but can string passes- blue collar earns 80K a week
Fireman-much respected -blue collar
Lawyers , Estate Agents , generally reviled white collar
Anyway thats a non pilot perspective, perhaps to be really facetious and pick up a common thread on PPrune how about defining it this way
Boeing Pilot -big hefty control device would be Blue collar
Airbus Pilot- little side stick, IT professional ,white collar
PB