Starbucks Corp. (NASDAQ:SBUX) is tightening the protective bubble around its CEO and loosening the rules on who pays for it.The coffee giant has removed limits on Chief Executive Officer Brian Niccol‘s use of the company's private jet, mandating that he fly exclusively on corporate aircraft for all travel, including personal trips, after a board-ordered security review. Under the revised policy, Niccol no longer has to reimburse Starbucks for non-business flights, reversing a prior arrangement that capped c ...