成せい層そう圏けん飛ひ行こう機き

noun

stratoplane

Historical term for a hypothetical high-altitude airplane designed to fly in the stratosphere.

• 成せい層そう圏けん飛ひ行こう機きは、かつて構こう想そうされた高こう高こう度ど飛ひ行こう機きの一いっ種しゅだ。

  The stratoplane is a type of high-altitude aircraft that was once conceived.