Found the answer to my question about the same time Cadet Delahanty troubled himself to peruse his orders. He is to call up Groome Transportation, which runs buses every half hour during the day between Atlanta Airport and Ft. Benning (a 1 hr 45 min trip). The cost is $39 each way. Compared to the prospect of waiting around for a short hop plane to Columbus and then getting a cab or bus, this is almost astonishing in its efficiency and cost effectiveness. (Before he forbade Mrs. Delahanty and me to show up to watch his jumps, I was planning to rent a car at Atlanta airport and drive myself. Come to think of it, I still might do it.)
Plus as I have told Cadet Delahanty, the Groome shuttle is quite similar to the famous New York City based Hampton jitney. Comely Swedish or Bulgarian exchange students serve on-board champagne cocktails and hand out Wall Street Journals and scented hot towels. Apparently this is the way they awaken you at 3:45 a.m. at Airborne School.
Grocery bills were indeed lower while Cadet Delahanty was away. This has been offset however by his determination to make up for missed barbecue.