Is money acquired from booking fictitious seats on an airplane, and lying to customers under the pretext that bookings are full, permissible or forbidden?

The question includes several matters: reserving seats with fictitious names, informing that the list is fully booked, and the ruling on the money earned. It is permissible to reserve fictitious seats if the responsible authority gives permission; otherwise, it is not permissible, and you must seek forgiveness and return what was missed. Your informing that the list is fully booked is not a lie. The money earned is lawful (halal (definition)) and remains lawful even with fictitious reservations, but the value of the seats that were missed must be returned to the responsible authority.