FlightGroup 

Flight data will differ for restrictions and for actual
flights

Element Group Information

Model

Flight | Flights
Children: Flight, Flights

Used By

Element Flights
Element Group LocationRangeGroup
Complex Types CarrierType, FlightType, SegmentAirType

Source 

<xs:group name="FlightGroup">
  <xs:annotation>
    <xs:documentation>Flight data will differ for restrictions and for actual flights</xs:documentation>
  </xs:annotation>
  <xs:choice>
    <xs:element ref="Flight"/>
    <xs:element ref="Flights"/>
  </xs:choice>
</xs:group>