Inability of an individual or a group to perform the given tasks up to the established standards. http://www.businessdictionary.com/definition/deficiency-performance.html.
TSA Requirements. The TSA requires that adult passengers ages 18 and older show valid photo ID at the security checkpoint. Children, however, are not required to present such identification. This does not mean, however, that children will be able to fly without it.
Also, Unaccompanied Minors in this age range will not be accepted for co-terminal connecting itineraries (such as changing from New York LaGuardia to New York Kennedy) because an unaccompanied child under 12 years may not use ground transportation unescorted. See Children Traveling Alone for more details.