long flights with 7-8 months?

Hi everybody!
So I just found out I'm pregnant with 6 weeks but I live in Europe and my sister (who lives in South America about 11 hours flight plus internal flights) has her wedding planed for novermber so I'm going to be 29 weeks. Do you think is there a risk to travel this far with my pregnancy? Is there a safe limit for traveling? I heard someone saying until 24 weeks is safe but later is not. Can someone share their experience or tips? Thank you all!