This is expensive, if pronounced dead in flight (on A/C) and not in Jetway airplane is quarantined for 48 hours! (no revenue for 2 days)
From the article no one on the aircraft pronounced her dead. Probably no one authorized to do so. What they said was that she "was found unresponsive early Monday aboard Delta Flight 53, about an hour out of Atlanta and about 11 hours after it took off."