A system that includes a ground unit that includes: a takeoff and landing platform; a landing and takeoff assisting module; and a housing. The takeoff and landing platform is arranged to hold and support an aerial unit during a first part of a landing process of the aerial unit and a first part of takeoff process of the aerial unit. The aerial unit is coupled to the ground unit via a connecting element. The effective length of the connecting element increases during the takeoff process and decreases during the landing process. The landing and takeoff assisting module is coupled to the takeoff and landing platform and is arranged to (a) lower the takeoff and landing platform into the housing during a second part of the landing process and (b) elevate the takeoff and landing platform during a second part of the takeoff process.