Pictured is the Terran heavy dropship, DS Resource. Dropships are heavily armored craft used for landing and retrieving troops from a 'hot zone'. Most will have significant offensive weapons, particularily the larger types. Most Dropships are short range, designed only to work in conjunction with a larger orbiting ship. Most dropships are capable of some degree of atmospheric and space flight. The roles of Dropships are generally military in nature, including landing troops or equipment on a planet, though they have been used in emergency situations such as evacuations.
Small Dropships carry only a dozen and are aerodynamic and use aerobraking during rentry and display aerodynamic lift for true atmospheric flight. In general they have a longer range compared to their larger counterparts.
The largest Dropships, such as the Terran Osprey II are able to land upright in a relatively small area using 'reverse thrust', though are of of extremely limited range. They can carry hundreds of troops and their equipment and can provide withering couterfire during a landing. They can be equipped to provide longer term base functions.