In Short:
When there are no Waypoints between staging base and target hex (caused by short ranges inbetween), then GA UNIT Missions (not sure if others too) are executed twice as often as set in the AD.
Additionally those additional Double-Missions are not being reported in the Air Execution Summary in any way.
From this I assume it is not a feature for flying short ranged ADs but it's a Bug.
I did not test/check if those Double-Missions are actually adding to Fatigue/Missions Flown/EXP of Pilots or whether they consume any Supplies ...or other possible weird things, since as said I assume it's a bug.
In Long:
So this is the AD set up. What should happen (and happens as expected when there are waypoints), are Missions on 2 days of the Week and 2 Missions per day of up to 200 Bombers each, giving 4 Missions with 800 Bomber Sorties per week. But as can be seen following, there were 8 Missions Executed onto the Hex. For context: "Strike Num"...
Each Mission normally has a independent Mission report, so an entry in the Air Execution Phase Summary, as can be seen following. It clearly shows 4 Mission were executed, 2 each day, as intended. But as shown it actually executed 8 Missions. As you can see the first Mission gives 45killed by using 189 Bombers. This matches the normal Report of the first Mission on map. As you can see in the first report following. What also adds up in this first Combat Report is the SUM of all planes in the Plane Type List (the number left of the commander picture). But as mentioned, there were 8 Missions reported on MAP and 4 being reported in the Air Execution Summary. (8 =/= 4). As you can see the second Mission in this Hex was not reported in the Air Execution Summary, neither as a separate Mission, nor by adding the Planes of both "Missions" together. What SUMs them together with the first "actual Mission" is the Plane Type List (the number left of the commander picture).[..] will be either automatically determined using the strike intensity set above or can be manually set by the player. It will set the number of missions that particular air directive will try to carry out during the air execution phase.