A vibration damping apparatus configured to damp a vibration of a target member includes a mass body, a base disposed on the target member, a support member disposed on the base and configured to support the mass body, a housing disposed on the base so as to surround the support member, an elastic member disposed so as to form a space in the housing and configured to apply a force to the support member, and a control unit configured to control a pressure of a fluid in the space by supplying the fluid to the space based on a vibration state of the target member.

Embodiments relate to dynamic stroking seats for vertical take-off and landing (VTOL) aircraft. Seat ballast tanks are attached to aircraft seats. The seats are sprung by a fixed or variable load energy absorption system. The weight of a user is determined and assigned to a corresponding seat of the user. Based on the weight of the user, the fluid level in the ballast tank is monitored and adjusted to achieve a target weight range.