ancient "thunderbirds" needed run way.

An ancient runway for flying reptiles called pterosaurs has been found in France, say researchers writing in a Royal Society journal. Led by Jean-Michel Mazin, the international team found a 150 million year-old landing strip in Crayssac in South West France. The "trackway" shows how the reptile landed feet first, then stuttered before walking on all fours. It is still is not known how they took off. The pterosaurs had a wingspan of one metre, but their feet were only 5cm long. Scientists think they possessed many of the flying skills of modern day birds. The researchers published their work in Proceedings of the Royal Society B: Biological Sciences.

Source: http://news.bbc.co.uk/1/hi/sci/tech/8209505.stm

So If you are looking for thunderbirds , maybe you should look for possible take off and landings sites.