Aircraft leases are leases used by airlines and other aircraft operators. Airlines lease aircraft from other airlines or leasing companies for two main reasons: to operate aircraft without the financial burden of buying them, and to provide temporary increase in capacity. The industry has two main leasing types: wet-leasing, which is normally used for short-term leasing, and dry-leasing which is more normal for longer-term leases. The industry also uses combinations of wet and dry. For example, when the aircraft is wet-leased to establish new services, then as the airline's flight or cabin crews become trained, they can be switched to a dry lease.