Blimp pilot Katharine Board sits at the controls of the Hood Airship en route from the Beverly airport to Boston, where it would assume its familiar position hovering over Fenway Park. Great view for a game, you might imagine, until you realize there is no bathroom in the cabin, which is attached to a 132-foot-long balloon that contains 70,000 cubic feet of helium. There’s room on board for four or five passengers, including the pilot, and it can get up to a maximum speed of 55 miles per hour.