Ask HN: Company training or best friend's wedding?

So I am at a crossroads between professional development and personal commitment ,and I could use some objective thinking.

One of my best friends is getting married over Labor Day, and I told him I wouldn't miss it, and I will go to it if there is any possibility. Unfortunately the company I work for wants to send me over for training in Switzerland for training for a client. I need to be at training Tuesday morning, and the only way I can make it is to be on a plane Sunday afternoon before the wedding.

Should I go down for the night before and hit the airport before the ceremony or should I say I am unavailable to go to Switzerland?