Most modern suitcases have built-in small wheels enabling them to be pulled along on hard flat surfaces by a fixed or extendable handle or by a retractable or stowable leash. Suitcases are a type of luggage.
A smaller, firmer suitcase, used mainly for transporting papers and office supplies is known as a briefcase.
Airlines attach tags to luggage which is transported as checked luggage. (Such checked luggage is occasionally lost or delayed, a significant worry for travellers.) Due to current security concerns, checked luggage may be inspected and the security staff may confiscate belongings that are prohibited on-board aircraft.