Didn't somebody once propose a CAX-LTN (or was it LCY) with a 146?
If the facilities at Carlisle were improved, maybe a decent route for Scot or Ryanair (CAX- London LTN/STN/LCY) as not much of major airports up that way (Glasgow & Pretswick to the North), Newcastle to the East & Manchester to the South. Flying would certianly beat the current Virgin trains Carlisle to London train service.
FC