On the plane, Deirdre (the chief air hostess) states that the plane can only lift off when every passenger is in their seats. When a Distressed Passenger on the plane begins to question whether flights have been grounded, as reports on his phone have stated, Deirdre attempts to control the situation by demanding that he take his seat and that the flight will take off soon.
Later, as she pushes the trolly of snacks and drinks around, she is rudely hands Marcus's wife two bottles of vodka as sympathy for Marcus' attidtude, and is later rudly pushed aside by Marcus as he makes his way to the bathroom.
She is present as the toilets trying to inform Marcus that they are about to land and that he needs to come out and take his seat. She is there when his wife opens the door to reveal the dead Marcus, and Deirdre tries to revive him. After the plane fails the land in Phoenix, and with Marcus' wife getting hysterical, Deirdre informs the other passengers that there is no other airport to divert to, as all others airports (including San Francisco ) are not responding to hails.
Marcus reanimates and scratches (and infects) Deirdre and his wife.
Deirdre is last seen comforting Marcus' wife, and she is shocked when Alex puts her down. She appears on the verge of passing out as Flight 462 starts to crash.