Is the sale of Hajj and Umrah services, which include airfare and accommodation, before obtaining the necessary permits and concluding final contracts, considered a sale of what one does not own, which is Islamically forbidden?

If the Hajj contract is based on known, unambiguous terms, such as delivering pilgrims to Mecca by air or sea and accommodating them appropriately, without specifying certain means that might be unobtainable, then there is no objection to it. This contract is considered a guaranteed ijarah (lease/hire), and it is not necessary to pay the entire fee upfront; rather, it is permissible to pay only a small portion, as long as the contract stipulates it. This is not a case of selling what one does not own, for selling what one does not own pertains to a specific item that may not be acquired, which leads to gharar (excessive uncertainty) that is forbidden by Sharia.