Under a dry lease the owner still provides the lessee with an aircraft – however, without a crew. No possession of the aircraft occurs under the terms of a wet lease, which makes it an exception to a typical lease.
Under a wet lease, the lessor has operational control. And unless an exemption exists, a wet lease signals the need for an FAA commercial operating certificate.
A wet lease is a normal part of a compliant Part 135 operation, while leased aircraft shared under Part 91 generally involve dry leases.