User blog comment:Kuras/Summer Event 2016/@comment-25833747-20160827000346/@comment-29735334-20160827130439

With 2 (F)BB and 2 CV(L/B) and the two mandatory DDs, the support type will always be shelling. Aerial support will only be triggered if you have 3 CV(L/B) in the support expedition fleet. You can refer to the Expedition page to see how support expedition works.