There are certain situations in which one will find oneself outside of one’s home on Hanukkah at the time of the Menorah lighting, such as when one visits one’s relatives or goes to a hotel while on vacation. If one were to leave one’s home after lighting time, that is, Tzet HaKochavim, then one should light the Menorah at one’s home, wait thirty minutes and then one may extinguish the flame before leaving. If, however, one were to leave before the Tzet HaKochavim and spend the night elsewhere, then one’s destination is would be considered one’s “home” and one would light there. If one were to leave before Tzet HaKochavim but will only arrive the next day, such as if one were travelling by airplane, then since such a mode of transportation does not have the status of a home, then one would be exempt from the Mitzvah of lighting the Menorah that night. There is an opinion that one would be able to light a flashlight on an airplane, but one should not utter the blessings in this case. Interestingly, Rabbi Shalom Schwadron (Shu”t Maharsham) writes that a train could have the status of a home since, especially in the past, people spend significant amount of time and sleep in the train. Furthermore, a soldier who is spending the night in the battlefield and does not have someone who could halachically light on his behalf, would be exempt from the Mitzvah.
It should be mentioned that although the ideal time to light is at Tzet HaKochavim, if the husband will be returning home later than that time, it is a universal custom to wait until he arrives before lighting.
Summary: Wherever one will be as of Tzet HaKochavim is considered one’s home with regards to lighting the Menorah. An airplane is not considered a home and therefore one would be exempt from lighting if one were flying.