"I dated a flight attendant for a while. One thing I haven't seen mentioned is that sometimes delays are caused by Flight attendants not showing up and the airline scrambling to get a back-up scheduled. Like a flight attendant was partying too hard last night and decided to call off 2 hours before that $1500 cross ocean flight you just popped on.
She loved to party as did a lot of her coworkers and were often hungover or "out of it" on flights. Even though pay was sh#t, their union made it very hard to get fired so call-offs were kind of no-big-deal."