I have been making good progress with the game, currently with loads of cash by just running small flights (GA/commercials). But I ran into an annoying problem, I cannot extend or upgrade my runway. I am trying to get medium flights to my airport, I need to extend the runway to be 800m long in order to accept medium flights.
I have extended the map - bought land around the runway to extend the map. Whenever I click to upgrade my runway to asphalt or any other option, nothing happens. No cash was deducted and nothing changed on the runway. I have lots of room for the runway to extend to the North and a little space to the South. No building or trees are blocking it. Please help!!!