Some scholars allow pilgrims who travel by air to enter the state of ihram in Jeddah so as to avoid hardship. This view may be applied in seeking the pleasure of Allah the Almighty by Hajj or `Umrah.
Sheikh Ahmad Kutty, a senior lecturer and an Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states:

Although many scholars prefer to offer the ruling that those who are undertaking Hajj or `Umrah must never pass the miqat without ihram regardless of whether they are traveling by land, sea or air, there is a minority of scholars who permit those who are traveling by air to do so from Jeddah.

Given the above, if you find yourself experiencing hardship to enter the state of ihram before boarding the plane or in the plane, coming as you are from distant lands, you may follow this ruling. This is a modern issue; Shari`ah is based on removal of hardship. There is enough evidence in Shari`ah to allow this ruling. However, if you do not find any hardship, it is best that you assume the state of ihram before arriving in Jeddah; either before or while arriving at the appropriate station (miqat) that is applicable to your point of journey.

May Allah the Almighty help us to apply the Shari`ah by taking into account not only its form but also its spirit and inner meanings. – Ameen.