Former Sec. of Defense Robert Gates, who served in the Bush and Obama administrations said this about sending air support:

"We don’t have a ready force standing by in the Middle East. Despite all the turmoil that’s going on, with planes on strip alert, troops ready to deploy at a moment’s notice. And so getting somebody there in a timely way – would have been very difficult, if not impossible. And frankly, I’ve heard, “Well, why didn’t you just fly a fighter jet over and try and scare 'em with the noise or something?” Well, given the number of surface to air missiles that have disappeared from Gaddafi’s arsenals, I would not have approved sending an aircraft, a single aircraft – over Benghazi under those circumstances."

https://www.washingtonpost.com/news/worldviews/wp/2013/05/13/robert-gates-on-benghazi-there-just-wasnt-time/

But don't let facts get in the way of a good smear campaign.