Delta Standby Crew JFK?
 

Our JFK to LAX yesterday evening left 4.5 hours late (and without us, because we had missed our connection to Australia) because tech crew personnel was late deadheading in from Boston, we were told. Does Delta have some standby aircrew for some types on duty at JFK ready to go for such contingencies? The assigned B767 was at the gate from the time we were (about 2 hours before schedule)

Sometimes these things happen.