Hello there BR0D4CZ. Thank you for reaching out and for this inquiry on where to place the registration number sticker of your drone. I would suggest placing the said sticker on your DJI Mavic Air 2 on a location where in it will not interfere with the air-vents of the said drone to prevent overheating or any issue while flying your DJI Mavic Air 2. In addition I hope that our fellow DJI co pilots can give out where they place the registration number sticker on there DJI drones. Thank you and enjoy flying.