A scenery being portrayed
I am pretty sure that themes on which William Folkner focuses and takes as a basis of his masterpieces are definitely : love, honor, compassion, and sacrifice. First of all, there is a prompt in question that is put in quotation marks. Love and compassion are the points which always were in need for people's relationships and honor with sacrifice, as told by Folkner in many of his works, are connected to more global sphere of demand - they are universal issues.
King using the phrase "flight's ground crew" refers to the people who have sacrificed a lot to make the freedom movement take flight. They are the people who have given their all but are not recognized for their sacrifices.