Parts makers, including Takata, are having to produce millions of additional inflators on top of those they supply for new vehicles around the world.
"It's our understanding that all of the affected automakers and their parts suppliers are continuing to work incredibly hard to manufacture and distribute replacement airbag inflators as quickly as possible," National Automobile Dealers Association spokesman Jared Allen told Automotive News.
Getting the recalled vehicles into dealerships for the repair also continues to frustrate the industry. In many cases, because the recall covers multiple model years, retailers and manufacturers sometimes no longer have valid contact data on owners, as cars have been resold privately over the years.
"Vehicle owners in the United States are not required by law to complete recall repairs," said Chris Martin, spokesman for American Honda Motor Co. "They must decide to bring their vehicles in for repair, and many customers, even with multiple notifications, have not yet responded.
"We are making continuous and concerted efforts to repair all remaining affected vehicles in the market. We have the replacement parts, and our dealers are prepared to make the necessary repairs."
NHTSA itself has launched several initiatives to speed the recall, including operating consumer help websites, while Honda hired investigators to track down used-car owners to get vehicles fixed.
NHTSA said Takata has "assured" it that the company will meet obligations in a consent order, and "remedy parts will continue to be available to vehicle manufacturers on schedule."
If Takata stops producing replacements, it would be up to the automakers to provide safe remedy parts for all affected vehicles, regardless of who produces the parts, NHTSA said.
Automakers have been shifting repair-parts business from Takata to rivals.
Martin said that Takata's bankruptcy will have no effect on Honda's ability to complete its recalls.
"Honda now uses recall replacement parts from alternative suppliers, not Takata," he said, "and we now have sufficient inventory of those inflators to continue recall repairs on all affected Honda and Acura models without any significant delay."