<?xml version="1.0" encoding="utf-8"?><!DOCTYPE Zthes SYSTEM "http://zthes.z3950.org/xml/zthes-05.dtd">  <Zthes><term><termId>31465633</termId><termName>variable-sweep aircraft</termName><termType>PT</termType><termNote><![CDATA[ Aircraft whose wings are so designed that they can be moved backward or forward in flight to optimize aerodynamic performance at widely differing speeds. ]]></termNote><termCreatedDate>2026-03-30 21:05:20</termCreatedDate><relation><relationType>UF</relationType><termId>31465634</termId><termName>aircraft, swing-wing</termName><termType>ND</termType></relation><relation><relationType>UF</relationType><termId>31465635</termId><termName>aircraft, variable geometry</termName><termType>ND</termType></relation><relation><relationType>UF</relationType><termId>31465636</termId><termName>aircraft, variable-sweep</termName><termType>ND</termType></relation><relation><relationType>UF</relationType><termId>31465637</termId><termName>swing-wing aircraft</termName><termType>ND</termType></relation><relation><relationType>UF</relationType><termId>31465638</termId><termName>variable geometry aircraft</termName><termType>ND</termType></relation><relation><relationType>BT</relationType><termId>31449671</termId><termName>fixed-wing aircraft by wing design</termName><termType>PT</termType></relation></term>  </Zthes>