I think, in this particular instance, Bishop wanted someone with him as he knew that if the field were occupied, he'd likely have his hands full. Not only would he have AAA to worry about, but also aircraft trying to take off.
As for Fry's reasons for not going, I'd rather not speculate. I wouldn't want to be seen as being "Anti-Fry."
But, come to think of it, if I am PRO-Bishop, then I must be anti-Fry!!
VBR,
Al Lowe