The Miqat boundaries (designated entry points for Ihram) apply whether you travel by land or air — passing them without being in Ihram when you intend Hajj or Umrah is not permitted. Since modern flights are fast, preparation is key. The practical approach is to perform ghusl (ritual bathing) and grooming at home or the departure airport, then change into your Ihram garments either before boarding or in the airplane lavatory before the Miqat is reached.
Most airlines operating Hajj and Umrah flights announce when the plane is approaching the Miqat boundary. If your airline does not make this announcement, use a GPS-based Miqat alert app (IhramOS includes this feature) or research your flight path to estimate the timing. Common Miqat points for air travelers include: Dhat Irq for those coming from the east, Yalamlam for those from the south, and Al-Juhfah for those from the north and west.
Once you are in your Ihram garments and approaching the Miqat, make your intention (niyyah) in your heart — specifying whether you are performing Hajj, Umrah, or both — and begin reciting the Talbiyah: 'Labbayk Allahumma labbayk...' If you realize you have passed the Miqat without entering Ihram, the majority of scholars say you must either return to the Miqat (if possible) or pay a fidyah (sacrifice a sheep in Makkah). To avoid this situation, it is safest to enter Ihram well before the estimated Miqat crossing.