Tree Removal

How to remove some tree and building so I can build my new Airport anywhere?

Check these.

http://www.scenery.org/design_utilities_b.htm

I cant find the software.. Can you please lead me to which software i need? Because I have tried Flatten and other. But I cant delete the tree and existing building

You could try this: http://www.scruffyduckscenery.co.uk/

Under Tutorials there is a section called 'Adding Objects'. My twisted logic tells me that if it shows you how to add opjects, it should reveal how to remove objects as well.

Keep in mind, this is a blind man who's groping in the dark speaking.