—Aviation is currently in the process of adopting IP as the network protocol for the Aeronautical Telecommunication Network (ATN), considering the fact that future communication services will be mainly based on data instead of analogue voice services. One of the crucial problems during this adoption is the mobility problem which is complicated by the fact that aircraft have a degree of world wide mobility and may make use of a variety of heterogeneous link technologies. Mobile IP, the standard IETF mobility protocol for the future, is investigated in this paper regarding its applicability to the aeronautical environment, based on realistic scenarios.