All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
It is permissible for you to perform ghusl for ihram and wear the clothes of ihram in your house before boarding the plane, but do not enter the state of ihram until you are in a location parallel to the miqat. His eminence Shaykh ‘Abdul-‘Azeez ibn Baaz had adopted this opinion, as he said:
The one travelling by a plane or a ship should enter the state of ihram when he reaches a place parallel to the miqat, just like the one coming by land. If one is parallel to the miqat, then he should enter the state of ihram in the air or the sea. He may do this directly before the miqat in order to be on the safe side because of the speed of the plane or the ship.
Entering the state of Ihram should be accompanied by saying: "Labbayk Allahumma-Bi-‘Umrah. (O Allah! I am here at Your service for performing ‘Umrah." Concerning landing in Medina or Jeddah; if the company you are travelling with intends to land in Medina first, then delay entering the state of ihram until after having visited Medina and assume ihram from the miqat of the people of Medina, which is now called (Abyar ‘Ali).
If they intend to land in Jeddah, then it is impermissible to delay Ihram after the Miqat.
Allah Knows best.