The airport will benefit from the Treasury and the Department of Trade.
Firstly the staff are asked to use the cheapest methods possible. This includes deciding if they can travel up and down in a day and fore go the cost of an overnight stay and the expense of food claims too!
Secondly how many staff who work in those departments actually live within easy access of a station on the East Coast mainline? Cross rail will bring Heathrow closer and if the LCY starts up again it will be ideally suited to the government offices at Stratford and Canary Wharf.
Thirdly the Department of Trade will have offices in a number if locations, including Belfast and Cardiff, these are locations where surface transport to Darlington is not great. Bring the airport into play.
Yes the new departments wont on their own keep the services going, but they will provide passengers, both inbound and outbound, which can only help.
They will also provide well paid jobs that will hopefully be taken up by people live within the airports catchment area. Who in term will use the airport for leisure reasons.