The US Federal Aviation Administration (FAA) said on Monday it is having oxygen masks in around 2,600 Boeing aircraft inspected due to issues with adhesive materials that could cause them to shift out of position. The FAA said that the fault “could result in an inability to provide supplemental oxygen to passengers during a depressurization event.” The inspection order comes after multiple reports from passengers that the oxygen mask units had shifted out of position because of a “retention failure,” according to the FAA. The issue affects both older and newer versions of the Boeing 737 aircra…