Dry/Wet leasing, from www.NBAA.org -
"The FAA classifies aircraft leases as either 'dry leases' or 'wet leases'. Under a dry lease, the aircraft owner provides only the aircraft and no crew. If at least one crew member is provided in the lease arrangement, this becomes a wet lease as defined in the FARs. A wet lease is an exception to the simple definition of a lease because it does not involve transferring possession of the aircraft. The lessor maintains operational control of the aircraft under a wet lease. Without a specific exemption, such as a time sharing agreement, or other options found under FAR 91.501, a wet lease requires an FAA commercial operating certificate."