As a former employee for fifteen years with Cobham at BOH. my take on the situation now is just the same as it always has been.
The god awful Catch 22 ... the airlines wont come until the external transport links are improved and the transport links won't be improved until there is the demand from airlines and pax...
The train station at Christchurch, literally just down the road has no connection with the airport and only the all stations stopping services call there. The road link from the A338 has been talked about for years but the only revenue spent has been on the installation of yet more speed cameras...