Next generation networks promise not only extremely high data rates and low latency, but also ubiquitous coverage and massive IoT. One of the major challenges is the guaranteed service provision even in cases of network failure (e.g. infrastructure damage, remote areas, flash crowd areas etc.). Flying nodes that will act as aerial base stations or relays could back-up the network fast and prevent any service interruption or even enhance network performance. This paper discusses the architecture and possible applications of flying modes in the frame of a 5G network supporting network slicing and lightweight virtualization. It also provides aerial LTE measurement results to support the feasibility check for using UAVs in two possible scenarios, i.e. network capacity enhancement and increasing network coverage.