It sort of spins out of bigger companies who tend to have a policy of "no more than 4 CO's in the same plane". It stems from when COs would all pile in to the same chartered plane because it was cheaper to do that and be flexible with time than to have them all drop what they're doing to sit on a commercial flight.

My company has the same policy for high enough management, but these days they all just travel solo on commercial flights anyway. It seems like it was different 20 years ago.

edit: I think they also maintain a car policy too, but I can't recall for certain.

Part of this is about making sure people are available at last minute notification. If you're in transit from Sydney, Australia to London, UK, you're out of action for 30+ hours plus the time to get over jet lag.

I am not buying that, People sleep and do morning routine for 10+ hours and on top of that they have personal life and weekends, you won't ask them to stop doing that so they will be available for you at last minute notification.

Whoever is oncall rotation for that week does.

Guess you're not familiar with the old term "pager duty".