Is it permissible to begin the steps of ihram from home (ghusl, perfuming, wearing ihram garments, and praying), then don stitched clothes over the ihram, and postpone the intention to enter the ritual (labbayka ‘umrah) and the talbiyah until a later time at the airport or on the plane, then remove the stitched clothes and make the intention and talbiyah, in order to avoid the cold weather during travel?

It is permissible for a pilgrim (Hajj or Umrah (definition)) to bathe, apply perfume, wear whatever clothes he wishes over the ihram (definition) garments, and engage in otherwise prohibited acts, as long as he has not intended to enter into the ritual. This is consistent with the action of Aisha, may Allah be pleased with her, in perfuming the Prophet, peace and blessings be upon him, before ihram, and with the statement of Al-Hafiz Ibn Hajar regarding the desirability of applying perfume when intending ihram and the continuation of its effect thereafter. Ibn Baz and Ibn Uthaymeen clarified that ihram is the intention to enter into the ritual, and that merely bathing, wearing ihram garments, or reciting the talbiyah (definition) does not constitute ihram unless accompanied by the intention. Therefore, it is permissible to do everything that a non-muhrim (one not in a state of ihram) does, even after bathing and wearing ihram clothes, as long as one has not intended to enter into the ritual. The intention is thus the condition at the Miqat (definition).