When building the airport you should be able to place airplane blueprints or real size models on the map.
Why it should be implemented:
This would be really helpful when building realistic airports. At the moment you are only able to see, if you have enough space for you airplanes, e.g. on two way tarmacs, when you have already airplanes using the tarmac. It would be nice to check in the build phase if there is enough space for the airplanes.
Images, references or additional content:
Look at the first picture in this thread: