PASSENGER TICKETS AS CONTRACTS

The most important right of the common carrier of passengers is his right to compensation. He carries for hire. This compensation he ordinarily collects by selling to the prospective passenger a ticket. Of these tickets there are many varieties, from the simple rectangular bit of cardboard, with the printed statement that it is good for one ride from X to Y, to the long coupon ticket, with elaborate provisions in fine print, providing for the passenger knows not what.

What is the legal character of this ticket?