Is it valid to pass the Miqat by plane without consecrating, then consecrate for Umrah from the Miqat of the people of Sham after arriving in Makkah, and does it not require a sacrifice?

If you enter into a state of ihram (ritual consecration) after passing the miqat (designated boundary), you are required to offer a dam (sacrificial animal), and returning to the miqat after having entered ihram will not absolve you of this. However, if you delay entering ihram until you return to the miqat and then enter ihram from there, you are not required to offer a dam.

Whoever passes the miqat intending to perform the rituals of Hajj or Umrah without entering ihram must return to the miqat to enter ihram from there. If they enter ihram from their current location (without returning to the miqat), they are required to offer a dam, even if they return to the miqat while already in a state of ihram. So, if one enters ihram from a point before the miqat, they are required to offer a dam, whether they return or not, unless they return before entering ihram and then enter ihram from the miqat.