A friend got a inflight promo code for an extra 5K sign-up bonus for the MP Explorer card and was wondering:

- How long (days, weeks) is that offer/code good for?
- Is it possible to use code for online-application: if so, where/how to enter it?
or must written application mail in?
- current sing-up bonus is 50K miles, however offer says "up to 65 K miles", how to get that amount?