I don't use org-mode myself, but
M-x apropos-variable org.*time turned up a couple of likely suspects. (I tried
org.*date first, but that didn't produce anything useful.)
It looks like you want to set
t and set
org-time-stamp-custom-formats to the way you want them displayed.
The value of
org-time-stamp-custom-formats appears to be a cons cell, where the car is the format for a date, and the cdr is the format for a date+time.
So I would try
(setq-default org-display-custom-times t)
(setq org-time-stamp-custom-formats '("<%b %e, %Y>" . "<%b %e, %Y %H:%M>"))