So it's not that complicated, is it? A flight case is:
- A reinforced box made of Astroboard (light wieght honeycomb polypropylene), HP laminate Plywood (popular types are as birch, poplar, or maple. (MDF is not suited for flightcases)
- Used for transporting equipment (usually delicate equipment or things that get moved around alot - think of roadies moving a bands gear)
- Usually custom made, but not always
Wikipedia lists a Flight Case as a Road Case and goes on to state that road case term (instead of Flight Case) "originates from its use for storing and shipping band equipment while the musicians were on the road."