Kinetic energy of a 50 ton aircraft at 70 m/s (about 140 kt) is about 125 MJ.
Jet-A1 has about 40 MJ/kg. That means that if it costs 3 kg of fuel per landing to carry the system, even a 100% efficient system is only just braking
even. Typically, a flight might use fuel equivalent to 5-10% of the extra weight it carries, which means that a system for storing and re-using 125 MJ weighing 30 - 60 kg would only just be worth it from an energy point of view, let alone a cost point of view. Tough to achieve!