Apparatuses are provided herein useful to sealing a gap between a movable flap and a stationary structure, such as a gap between a gas turbine engine nozzle flap and a corresponding sidewall. An apparatus for sealing such a gap may be a dynamic skirted leaf seal which may include a flap arm, a wall arm opposite the flap arm, and a support arm disposed between the flap and wall arms. A distal end portion of the flap arm may comprise a first skirt and a distal end portion of the support arm may comprise a second skirt that engages the first skirt. When positioned in a gap, the skirted leaf seal may exert a force to urge the first flap arm towards the flap and to urge the wall arm and the support arm towards the structure to seal the gap.