I presume the hybrid electric aeroplane takes off using a fossil-fuel engne, cruises on electrics and lands on whatever it most appropriate, or have I got hold of the wrong end of the stick?
You would take off using primarily electrical power - e.g. a 220 horsepower electric motor might just weigh 25 kg. Batteries to power such a motor at full power would weigh about 20kg/minute.
Some of the very clean, smaller aircraft may easily cruise at 20 horsepower or so. If you cruise at 20 horsepower, you need 2kg of batteries for every minute of flight. 120 minutes endurance = 240kg of batteries, which is a lot. On the other hand, if you power the cruise with an internal combustion engine, it could weigh 10-15kg and sip just a few liters an hour.
Probably in practice you would want some different balance, but by adjusting the ratio of IC:electrical power and the amounts of batteries/fuel you should be able to contrive a system that will outperform an aircraft powered by either power source individually.