Pilots and cabin crew swap their traditional gold shoulder stripes for pink ones throughout October.
Fly Pink, an aviation industry initiative, was founded in Australia by QantasLink pilots in 2015.
It champions breast cancer awareness, early detection and research.
Cook’s UK, Scandinavian and German (Condor) airlines will all take part. Two Cook aircraft have adopted the campaign’s pink bow motif.
Pilots will wear pink epaulettes and cabin crew pink scarves or ties instead of their traditional yellow.
Captain Linton Foat said: “The initiative is driven entirely by our employees across the group airline from pilots and crew throughout our head offices to our chief executive. It makes me really proud to fly for Thomas Cook Airlines.
“With the disease affecting one in eight women and personally touching many of the team, there is a real desire to support and raise awareness. We are supporting Macmillan Cancer in the UK and will be raising money on board all of our aircraft for the month of October.”
October is also International Breast Cancer Awareness Month and Cook expects its contribution to the campaign to raise awareness among some 800,000 passengers.