Starting today, extremely overweight passengers on United Airlines may be forced to buy an extra seat to accommodate their extra padding. A spokeswoman for the airline tells Bloomberg News the policy is being implemented in response to "hundreds" of complaints, and that until today more svelte customers had no choice but to "share their seat with the oversized guest." According to the new rules, an obese flier may be required to pay for an extra seat if he or she can't buckle the seatbelt (even using the seatbelt extender) or can't put the armrests down when seated. If the flight is not fully booked and two empty adjacent seats are available, flight attendants will relocate the passenger, free of charge. But if the flight is full, the passenger could be bumped to another flight or charged for an upgrade. Similar policies are already in effect at eight other domestic airlines, including Delta and Southwest. But up in ever-courteous Canada, the Supreme Court ruled that airlines must provide an extra seat for wide ends free of charge.