From Daily Mail (caution: tabloid):
If the world’s wealthiest and best-connected people knew a catastrophe was approaching, their private jets might reveal it before officials sounded the alarm.
That theory has inspired a programmer to build an online ‘Apocalypse Warning System’ that monitors more than 31,000 private and business aircraft for signs of an unusual exodus. The website continuously counts how many of the jets are airborne and compares the figure with historical patterns, searching for a surge that could suggest powerful insiders are responding to a looming crisis.