Fliers may want to have their tickets in hand before catching their planes, but the airline companies are doing everything they can to bring forward cost-saving ticketless flight —no paper needed, just a ticket number and a photo ID. Anyone who buys a Northwest E-ticket through the airline’s computer service by June 16 will get an award. Next time you fly, you can buy another ticket for a friend for $ 99,good anywhere in the US or Canada through February, along with the lowest ticket prices.Some airlines offer extra frequent-flier miles for the ticketless crowd. And there are rising punishments for paper lovers. American, Northwest, United, and US Airways have raised the cost for lost-ticket replacement to $ 70 from either $ 60 or $ 50 last week. The airlines insist that the increase in price is not meant to push travelers toward E-tickets but only covers the increasing cost of replacing and tracking a missing ticket. To encourage people to take ticketless flights, the airlines______.
A．sell their tickets for $ 99 from June to February the following year B．let travelers go to both the US and Canada with the same tickets C．allow each traveler to have an extra $ 99 ticket for a friend of theirs D．offer ticketless travelers free miles to fly in the US