2 problems I am having with your game:
1. I think that the exponential increase in the cost for markets and hangers is hurting your game. Instead of building the market, which would imply that you own it and should be getting revenue from it for all trades made, you should have to by an "Import/Export Licence" you could make them permanent or last a certain number of game days but they should be a fixed and relatively low price.
2. The need for special items to open up trade routes, this has twice got me stuck where I was forced to spend these special items to continue the game. Being forced to spend real money to make a basic concept in a trading based game is not a good idea because it comes across as extortion to the players. Or at least it does to me.
The game started fun and seems to have potential but I am quickly losing interest because of the mechanics. Fix it soon please
 "Aviator"){kind=icon}
 "Wake Up the Box 4"){kind=icon}