Customs officials denied the airline's allegation.
The trans-Atlantic flight's captain was told by a customs official at Bradley International Airport in Windsor Locks that passengers couldn't get off the plane until more immigration officials arrived, Greg Dawson, an airline spokesman in London, said in an e-mail to The Associated Press. It took more than two hours for the officials to arrive, he said.
The London-to-Newark, N.J., was diverted because of storms. late Tuesday and early Wednesday in rising heat and darkness. Travelers said they were offered water but no food; some fainted.
The three-hour limit on tarmac strandings that went into effect in April or international flights by U.S. carriers, although U.S. carriers are required to have contingency plans for returning passengers waiting for prolonged periods on planes to airport terminals.
U.S. Customs and Border Protection did not receive a call from the pilot, and no one from the agency refused a request to allow passengers off the plane, said Theodore Woo, an agency spokesman in Boston.
Customs officers headed for the airport "as soon as we got the call at 11 p.m.," Woo said. At that point, customs had enough officers to "escort passengers to a safe area," he said.
Airport officials have said there was only one customs official at the airport Tuesday night when the flight arrived in Connecticut.
The airport called for customs inspectors around 11 p.m. when it learned the Virgin flight was canceled, said John Wallace, a Bradley spokesman. Passengers were allowed off the plane about an hour and 15 minutes later, when customs officials arrived, he said.
Bradley's only regular international passenger flights are to Canada, and it does not house many customs agents, Wallace said.