The standard lightning waveforms used for the testing of aircraft are based on downward lightning. However, there is evidence suggesting that lightning to aircraft is different from negative downward lightning. Also, carbon fiber composite materials are being used extensively in wind turbines and aircraft which comprise small, sensitive electronics as part of avionics and control systems. In this paper, data on upward flashes obtained in Switzerland are used to critically assess the applicability of the standard current waveform for lightning testing of aircraft and wind turbine blades.