Airfare Research

So I have been looking around for airfare hoping that we will be able to leave in the October time frame.  Most everything I have been looking at is north of $650 per person for a one-way ticket from Portland, Oregon to Lima, Peru. That is with the exception of the flights that I have been looking at through google flights. Depending on which day in October we leave I can get them for $414 per person including the checked baggage fees.  We have a doctor appointment on August 8th to ask our doctor if he thinks Summer is ready to travel yet. I hope if he says yes that these prices are still available.