7500 is the aircraft transponder code used to indicate a hijacking.
Most modern aircraft - especially those on intercontinental routes - have crew break rooms or "rest areas" aboard, where the crew can get some sleep on long flights, which is perfect for hiding something like a dead body, away from the passengers.
Originally had an August 31st 2012 release.
The background of the start menu has clouds that, if you look closely, resemble screaming faces
A plane this size would have a pressurized cargo hold, with some type of way to get there. That is where an actual dead body would be placed. Also, death on board a flight would be an unnatural death, forcing the plane to a landing ASAP, so authorities could investigate the cause.