The chief executive of Boeing insisted on Wednesday that the planemaker only allows jets to fly when “100%” confident of their safety, as it faces intense scrutiny – and anger – following a cabin panel blowout on an Alaska Airlines flight.Boeing fully understands “the gravity of the situation”, Dave Calhoun said in Washington, as he prepared to meet a string of US senators.His company has been trying to reassure airlines, regulators and passengers after a cabin panel blew off a brand-new 737 Max 9 jet durin ...