Atleast at JFK, cargo is handled by another company that works for Delta. Sometimes the clowns bring the cargo to the aircraft at the last minute and sometimes they dont bring it at all. Id play it safe and go UPS or Fedex. Too many factors can mess ur shipment up at the airport, ive seen it happen. Things fall out of cargo carts, slackers dont bring the cargo on time and sometimes theres just no space for cargo on a flight and passenger bags take priority over everything else. Good luck next time, sorry for ur loss. Once your in the mix here you see what goes on behind the scenes to make things happen and its more than you would think and alot of people are involved down the line.