That is an absolutely pathetic and unbelievable excuse. They would have had no idea how long the people there might hold out. They could have put assets in the air and had up to two hours to decide whether to use them while they were enroute. But nothing was deployed.
Panetta's excuse is no different than a field commander getting a call from one of his squads saying they were pinned down and being overrun and responding "We probably can't get to them. Let's forget about it."