Funny you should mention that, as from the 5th September there will be road works on the slip road from the A338 (Wessex Way) at the airport junction.
There has been a copy of the info floating around college this week, and basically the slip roads and the bridge above (the one you can use if you are coming from Southbourne/Christchurch direction) are being resurfaced. They will be closed at various times to be posted on signs at the road works, but there is no indication when this will be. The bridge will be one lane only with traffic lights.
I guess you guys don't start at the college until the week after, so we may have some idea of the extra delays it causes by then. If anybody as an A-Z yet, and if you would usually use the A338, the other routes will involve either driving through Pokesdown to Iford then in on the bridge over the A338, or via Kinson/Redhill area through Parley Cross from the north.
What fun. (I think I might cycle LOL)