The travel industry is bracing for a painful holiday season as people scale back their discretionary spending. But that is good news for anyone who has yet to book a winter getaway, with hotels, airlines and cruise operators introducing last-minute deals to entice vacationers. Holidays are the busiest time of year for most travel companies, a season when they command the highest rates for popular winter destinations. “There is no part of the industry that will go unscathed,” said Henry H. Harteveldt, a travel analyst with Forrester Research.