The concept of passenger air transport has not changed since its beginning. However it has to transport more and more people. Clip-Air provides a revolutionary concept for air transport by carrying up to three capsules (about an A320 without wings and tail) below a flying wing. These capsules could be loaded with either passengers or freight, which provides modularity to the concept. This project studies the energy demand of these capsule and proposes an alternative solution fed with renewable fuel. Compared to the actual system the best results obtained with the alternative solution are when it is fed with either liquid hydrogen or liquid methane. It allows to save, at maximum, nearly 20% of the mass of the actual system.