New Delhi: Air India has apologised and offered a travel voucher of USD 350 each to the passengers of the San Francisco flight that took off from the national capital after a delay of more than 30 hours. There were 199 passengers on the flight, according to a source. After a delay of over 30 hours, the flight took off from the national capital at 2155 hours on Friday and landed in San Francisco at 1245 hours (IST) on Saturday. The flight duration was around 16 hours. “Please allow me to sincerely…