What is the difference between an aeroscraft and an airship? I stumbled across this site when I was searching for info about airships. They have main three products - aerocraft aeroscraft, airship and aerostat. Aerostat is clear for me somehow. But what is the key difference between aerocraft aeroscraft and airship?
Aeroscraft is their brand name. It does not mean anything generally.

The general terms are:

"Aircraft" (but not "aerocraft") means any machine capable of sustained flight in the atmosphere.

"Aerostat" is a lighter-then-air aircraft. That is it has large shell filled with gas with lower density than air and uses buoyant force on that for lift. This includes balloons, hot-air or gas filled, tethered balloons and airships.

"Airship", or "dirigible" is an aerostat equipped with propulsion that allows it to move on it's own (as opposed to balloons that are tethered or carried by wind).