A troop carrier is a vessel designed or tasked with the transportation of infantry. It may a purpose-built military passenger transport vessel, however it has been common practice throughout much of the 19th and 20th centuries to use ocean liners chartered or commendeered from civilian lines. In the past, governments have subsidized the production of liners so they might be availed for troop transportation, with an additional benefit of maintaining domestic shipbuilding capacity and expertise. A troop carrier which can land at unprepared beaches is known as a landing craft. Modern use of troop carriers has generally been superceded by aircraft.