I never knew this about airport service workers; I had naively assumed that the people who clean aircraft and airport bathrooms were better paid, possibly with collective bargaining and a union to protect their rights. Not so; many of them are employees of companies who contract to do the service work at the lowest possible wages. Remember, if you or a family member use the common "wheelchair service" at your airport this weekend, please tip the person who pushes the chair. They're working for peanuts. The Secret Life of the American Airport Worker I’ve spent the last six months investigating…