Here's an odd thing about upgrading with LifeMiles on Avianca that may be useful to know for someone -- you can't upgrade a flight unless all segments offer Business class. In my case, I was flying LAX to SAL and SAL to RTB (Roatan, Honduras). The latter segment is on a prop plane with economy class only. I knew that and was willing to cough up the miles for business class from LAX to SAL. After a long time on hold, the call center representative came back on the line and said he tried everything, even consulted another department, and apparently their system won't let the upgrade go through unless it can book a business seat on the entire one-way flight, even if the reason it can't is that there IS no business class on part of the itinerary.