AIT is the second half of usual Army IET for any MOS that doesn't attend OSUT. At AIT a soldier will be trained in their job essential skills. Every AIT is different, from signal corps training at Fort Gordon to military intelligence training at Fort Huachuca.

Aside from training soldiers in any technical skills they'll need, AIT usually continues what BCT started in weeding out the soldiers from the civilians. Some parts of AIT are significantly harder, with more study intensive testing, higher physical fitness standards (in Basic you need to pass at 50%, in AIT you need to pass at the Army's 60% standard ).

Depending on which AIT one goes to, a soldier may have significantly more freedoms than they had in basic. From my own experience I can attest to having weekends off from training and priveleges like leaving post on weekends and shopping at the PX when not in training during the day. During AIT we were also given more downtime than in basic training, my training days were only 6 hours long as opposed to 8+ hours of training in BCT.

If you have any further questions regarding military basic combat and advanced individual training, be sure to /msg me and let me know what I left out!