Few highlights from my current company:
* All airfare is to be booked through the company designated travel agent (which charges a $10 "ticketing fee"!).
* All airfare must be charged to either the company American Express or Diners Club card.
* Employees may fly Business Class for scheduled flights more than three hours in duration.
When I was a contracted at large Boston bank, I got a glimpse of their travel policy, which was more comprehensive. It included items like: if employee used own miles for an award ticket to use on business travel, the employee can be compensated for 50% of the value of that fare and if employee chose to stay with friends/family in lieu of hotels, company will reimburse for meal/gift with/to friend.