"It was a like a bomb going off," Dr Smith told NZPA from Los Angeles airport.
Flight NZ2 was hit by the bolt as it climbed out of Auckland in atrocious weather.
The flight had been delayed by about an hour because of the weather before taking off about 10.30pm.
"We took off, and as we were climbing out of Auckland ... suddenly there was a blast like a bomb going off and the plane took a direct lightning hit ... it was a massive blinding flash of light."
It was accompanied by an ear-shattering clap of thunder.
Dr Smith said the plane didn't falter; "I expected immediately the plane to lose power but no she just kept climbing".
The captain told passengers all instruments were showing the systems were functioning properly and continued on. If the plane turned back it would have had to have flown for hours to get rid of enough fuel.
Dr Smith said the seats on the flight were full with lots of children because of the start of school holidays.
"It was wonderful nothing went wrong."
He said no one was too upset as there was no warning of the bolt and it was over as quickly.
Dr Smith was going to London on a private trip.
The flight to London was delayed for four hours in Los Angeles while the plane was checked over.
