Has my 5 year old got autism

My five year old boy flaps his arms and jumps up and down when he is excited. I had to go to his school the other day to see his teacher and she told me they are concerned about his arm flapping and he is unable to look at the teachers and make eye contact when he is spoken to.  They also said he is sometimes aggresive (aggressive) towards other children.  When we are at home he will be watching tv and suddenly shout out for no apparent reason.  Is this autism?

[Natta1980]

Probably would not hurt to get professional opinion

Does he have difficulty communicating at all? I.e. back and forth conversation?

That has to be present for all autism spectrum disorders