In Japan on Wednesday, aviation regulators indicated that they were satisfied with Boeing’s modifications and would declare the planes fit to fly as early as Thursday.

“Boeing has come up with a fix that addresses a very wide range of potential problems,” said Hirohiko Kawakatsu, an air safety official at the Ministry of Transport. “In that regard, we see no problems with the fix.”

Mr. Kawakatsu said he did not expect the ministry to ask for substantial additional changes to the batteries. Japan’s approval would allow All Nippon Airways and Japan Airlines to resume flights of the 787. Together, the two airlines own about half of the 787 jets delivered by Boeing so far.

The Ministry of Transport indicated that it was waiting until Wednesday’s conclusion of a hearing in Washington by the National Transportation Safety Board on its investigation into a battery fire on a 787 parked at Logan Airport in Boston in January as well as the F.A.A.’s initial certification of the lithium-ion batteries in 2007.

To date, investigators have not determined what caused the fire in the battery in Boston or smoke from a 787 battery in Japan in January. In its earnings report on Wednesday, Boeing said its first-quarter earnings jumped 20 percent to $1.1 billion, or $1.44 a share, from $923 million, or $1.22 a share, a year earlier. Revenue fell 3 percent to $18.89 billion from $19.38 billion. That was partly because Boeing had delivered only one 787, because of the battery problems, compared with five in the same quarter a year ago.