The thing to also realise in the differences between HIV and Influenza is that influenza is a respiratory virus, it's droplet spread and it invades the cells lining the air ways - nose, trachea and sinuses while HIV does not target those. It would take fundamental redesign of the virus for that to happen - HIV targets immune cells in the linings of the membranes and it could target these cells in the nasal passages too - they are far fewer in number than the default cells which line the airways - also the amount of virus needed to lead to infection is quite large. You'd drown from the amount of fluid entering the airways before getting HIV this way. The virus also does not occur in secreations from the respiratory tract so you can't sneeze out HIV, it is secreated into saliva but you need a large amount to transmit it via kissing (having wounds in the mouth or inflammation reduces this amount). Someone with a high viral load in the body could spit
on a fresh would and possibly transmit HIV that way but that hasn't been documented yet. Neither has any insect vector transmission as the inoculum is too small and conditions in the mosquito HIV unfriendly.
However, when people say 'airborne' we must clarify what that means. Usually viruses spread in droplets, not dried out airborne spread like say anthrax. Anthrax is not a virus but a bacterium and can survive in the dry environment, it is inhaled into the lungs and replicates there. Ebola can spread via droplet spread but not through release into the atmosphere - someone very ill with ebola in the airways would need to sneeze or cough up at you.
well, if the virus could find it's why into the lymphatic system, then it's just a free-for-all... the problem is that the virus would have to be extremely lucky to get into the lymphatic system with out detection.
There is a possibility that the virus could infect other cells and not just the white cells (i can't remember the specific cell it most enjoys attacking, i think it's the CD-4 helper T cell, but i can't be sure), where it could infect avioli epidermal cells, if that happens, then the virus could be coughed up, and spread like that... however, that is quite unlikely because the virus just doesn't have a large enough infection base for such a mutation to take place anytime soon... however, if the number of those infected suddenly rose ten fold, there is a possibility...
But like most things in nature, mutations are highly erratic and the chance of HIV becoming an airborn disease are extremely low... So in that sense, you can rest easy...