If a Ben HaAretz is flying to Hutz La’Aretz, can he fly on what is Second Day Yom Tov in H’ul? What is the state of the plane in the air? I assume that landing when still 2nd day Yom Tov would be a problem - but what if he were to land an hour after Yom Tov in Hul? Is there a problem of Marit Ayin?

There is no problem with a Ben Eretz Yisrael flying on the second day and landing after the day is over in Chutz l'aretz. If landing on second day one should stay in the airport until after Yom Tov.