One example why regionals are important to legacies:
"Now 'we are focused on brand perfect days' which would include the 2,400 of Delta’s 5,500 daily departures [~44%] that are operated as Delta Connection flights by six regional partners including Endeavor Air, which Delta owns."
Yet:
"Regional airlines also suffer financial problems, largely as a result of being squeezed because the three global carriers bid out regional flying to the lowest bidder."
Delta, Not Content, Wants To Fix The Unfixable: Regional Operations And Long Security Lines