A、Because the person who had invited him died in an air crash. B、Because the American film producer was on the plane that crashe

James wrote a play for television about a family who came to England from Pakistan. The play was surprisingly successful, and it was bought by an American TV company.
      James was invited to go to New York to help with the production. He lived in Dulwich, which is an hour’s journey away from Heathrow Airport. The flight was due to leave at 9:30 a.m., so he had to be at the airport at about 7:30 in the morning. He set his alarm for 5:45 a.m. and went to sleep.
      Unfortunately he forgot to wind the clock, and it stopped shortly after midnight. As James woke up and turned on the radio he was surprised to discover that it was 9:55 already.
     He was so upset but could do nothing now. He was just pouring himself a cup of tea when the clock struck ten. The announcer began to read the news: "Reports are coming in of a crash near Heathrow Airport. A Boeing 707 to New York crashed shortly after taking off this morning. Flight number 2234." James turned pale.
     "My flight," he said out loud. "If I hadn’t overslept, I’d have been on that plane."