Honda plans to recall 21 million more vehicles worldwide to fix defective airbags supplied by the equipment manufacturer Takata, a senior executive at the carmaker said on Friday. The Japanese automaker made the estimate public after American regulators more than doubled the scope of an airbag recall in the United States, identifying another 35 million to 40 million vehicles they said needed fixing. Honda, which is Takata’s biggest customer, is now recalling 51 million vehicles in total. The Honda executive, vice president Tetsuo Iwamura, did not specify how many of the vehicles that Honda plans to recall are in the United States or other countries. But many of the vehicles are likely to be part of the American recall expansion, which was ordered last week by the National Highway Traffic Safety Administration. Takata-made airbag inflaters can explode with too much force when the airbag deploys in a crash, sending shrapnel shooting into a vehicle’s cabin. The fault has been blamed for at least 11 deaths worldwide and more than 100 injuries. Replacing tens of millions of Takata-made inflaters is a costly undertaking for carmakers, about a dozen of which have been caught up in the crisis. Honda reported a rare quarterly loss on Friday because of expenses stemming from the recall. Honda said it had set aside an additional 267 billion yen, or $2.45 billion, to cover recall-related costs. That brought its total recall expenses for the financial year that ended in March to ¥436 billion. It's so bad. So many automakers should cover additional costs.