You had this shop between levels to upgrade stuff. After several levels I went to a new airport, and was extremely disappointed to find that all the up grades I bought were gone. Most games let you keep your upgrades even at new locations, but not this one. The upgrdeas were not cheap either. So pay a pritty penny for an additional hanger, or a plain pinter, or parking space just to see it disappear in a few levels. SO WHAT'S THE POINT. Also when I click on the runway, or gate, sometimes it would give me a red X even though I know I selected the correct plain, and clicked right on the runway or gate, or such. That farther adds to the frustration. The graphics were nothing special either. Also gets quite monotonous and boring.