I was a sportman class so i was invited but there were not many in my class and then i had to compete at all the ama pattern events in my state /US years before hand .. The pros back then were invited also to the world nats in Muncie but we knew who most of them were . I have been out of it for a long time but even now i think you have to compete at so many AMA sanction events and get a score rating before competing at the US nats . Anyone can go watch and its not fun with 7 judges watching you fly and a 1000 or so people also. http://centralhobbies.com/instructional/ama_rules.pdf You fly pattern Kurt ?